Nofollow
Encyclopedia
nofollow is a value that can be assigned to the
of an HTML
s that a hyperlink
should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing
from occurring.
. Believing that comment spam affected the entire blogging community, in early 2005 Google
’s Matt Cutts
and Blogger
’s Jason Shellen proposed the value to address the problem.
The specification for
, IETF, and/or W3C.
announced in early 2005 that hyperlinks with
. In addition, the Yahoo and Bing search engines also respect this attribute value.
On June 15, 2009, Matt Cutts
, a well-known software engineer of Google, announced on his blog that GoogleBot will no longer treat nofollowed links in the same way, in order to prevent webmasters from using nofollow for PageRank sculpting. As a result of this change the usage of nofollow leads to evaporation of pagerank. In order to avoid the above, SEOs developed alternative techniques that replace nofollowed tags with obfuscated JavaScript code and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and JavaScript.
More sophisticated server software could spare the nofollow for links submitted by trusted users
like those registered for a long time, on a whitelist, or with an acceptable karma level. Some server software adds
The widely used blogging platform WordPress
versions 1.5 and above automatically assign the
software, which powers Wikipedia
, was equipped with nofollow support soon after initial announcement in 2005. The option was enabled on most Wikipedias. One of the prominent exceptions was the English Wikipedia
. Initially, after a discussion, it was decided not to use
In May 2006, a patch to MediaWiki software allowed to enable nofollow selectively in namespace
s. This functionality was used on pages that are not considered to be part of the actual encyclopedia, such as discussion pages and resources for editors.
nofollow is a value that can be assigned to the
of an HTML
s that a hyperlink
should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing
from occurring.
. Believing that comment spam affected the entire blogging community, in early 2005 Google
’s Matt Cutts
and Blogger
’s Jason Shellen proposed the value to address the problem.
The specification for
, IETF, and/or W3C.
announced in early 2005 that hyperlinks with
.Google (January 18, 2006), Preventing comment spam, Official Google Blog, retrieved on May 29, 2007 In addition, the Yahoo and Bing search engines also respect this attribute value.Microsoft (June 3, 2008), Bing.com, "Bing Community", retrieved on June 11, 2009
On June 15, 2009, Matt Cutts
, a well-known software engineer of Google, announced on his blog that GoogleBot will no longer treat nofollowed links in the same way, in order to prevent webmasters from using nofollow for PageRank sculpting. As a result of this change the usage of nofollow leads to evaporation of pagerank. In order to avoid the above, SEOs developed alternative techniques that replace nofollowed tags with obfuscated JavaScript code and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and JavaScript.
More sophisticated server software could spare the nofollow for links submitted by trusted users
like those registered for a long time, on a whitelist, or with an acceptable karma level. Some server software adds
The widely used blogging platform WordPress
versions 1.5 and above automatically assign the
software, which powers Wikipedia
, was equipped with nofollow support soon after initial announcement in 2005. The option was enabled on most Wikipedias. One of the prominent exceptions was the English Wikipedia
. Initially, after a discussion, it was decided not to use
In May 2006, a patch to MediaWiki software allowed to enable nofollow selectively in namespace
s. This functionality was used on pages that are not considered to be part of the actual encyclopedia, such as discussion pages and resources for editors.
nofollow is a value that can be assigned to the
of an HTML
s that a hyperlink
should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing
from occurring.
. Believing that comment spam affected the entire blogging community, in early 2005 Google
’s Matt Cutts
and Blogger
’s Jason Shellen proposed the value to address the problem.
The specification for
, IETF, and/or W3C.
announced in early 2005 that hyperlinks with
.Google (January 18, 2006), Preventing comment spam, Official Google Blog, retrieved on May 29, 2007 In addition, the Yahoo and Bing search engines also respect this attribute value.Microsoft (June 3, 2008), Bing.com, "Bing Community", retrieved on June 11, 2009
On June 15, 2009, Matt Cutts
, a well-known software engineer of Google, announced on his blog that GoogleBot will no longer treat nofollowed links in the same way, in order to prevent webmasters from using nofollow for PageRank sculpting. As a result of this change the usage of nofollow leads to evaporation of pagerank. In order to avoid the above, SEOs developed alternative techniques that replace nofollowed tags with obfuscated JavaScript code and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and JavaScript.
More sophisticated server software could spare the nofollow for links submitted by trusted users
like those registered for a long time, on a whitelist, or with an acceptable karma level. Some server software adds
The widely used blogging platform WordPress
versions 1.5 and above automatically assign the
software, which powers Wikipedia
, was equipped with nofollow support soon after initial announcement in 2005. The option was enabled on most Wikipedias. One of the prominent exceptions was the English Wikipedia
. Initially, after a discussion, it was decided not to use
In May 2006, a patch to MediaWiki software allowed to enable nofollow selectively in namespace
s. This functionality was used on pages that are not considered to be part of the actual encyclopedia, such as discussion pages and resources for editors.Wikipedia (May 29, 2006),
rel attributeRel attribute
A link relation is a descriptive attribute attached to a hyperlink in order to define the type of the link, or the relationship between the source and destination resources. The attribute can be used by automated systems, or can be presented to a user in a different way.In HTML these are designated...
of an HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
a element to instruct some search engineWeb search engine
A web search engine is designed to search for information on the World Wide Web and FTP servers. The search results are generally presented in a list of results often referred to as SERPS, or "search engine results pages". The information may consist of web pages, images, information and other...
s that a hyperlink
Hyperlink
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...
should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing
Spamdexing
In computing, spamdexing is the deliberate manipulation of search engine indexes...
from occurring.
Concept and specification
Thenofollow value was originally suggested to stop comment spam in blogsSpam in blogs
Spam in blogs is a form of spamdexing. It is done by automatically posting random comments or promoting commercial services to blogs, wikis, guestbooks, or other publicly...
. Believing that comment spam affected the entire blogging community, in early 2005 Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
’s Matt Cutts
Matt Cutts
Matt Cutts works for the Search Quality group in Google, specializing in search engine optimization issues. In an interview with USA Today in June 2008, Cutts provided advice on how to optimize search results on Google.-Career:...
and Blogger
Blogger (service)
Blogger is a blog-publishing service that allows private or multi-user blogs with time-stamped entries. It was created by Pyra Labs, which was bought by Google in 2003. Generally, the blogs are hosted by Google at a subdomain of blogspot.com. Up until May 1, 2010 Blogger allowed users to publish...
’s Jason Shellen proposed the value to address the problem.
The specification for
nofollow is copyrighted 2005-2007 by the authors and subject to a royalty free patent policy, e.g. per the W3C Patent Policy 20040205, and IETF RFC 3667 & RFC 3668. The authors intend to submit this specification to a standards body with a liberal copyright/licensing policy such as the GMPGGMPG
GMPG or Global Multimedia Protocols Group is an informal organization who engages in experiments in Metamemetics.It was first mentioned in 1992 by author Neal Stephenson in his novel Snow Crash....
, IETF, and/or W3C.
Introduction and support
GoogleGoogle
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
announced in early 2005 that hyperlinks with
rel="nofollow" would not influence the link target's PageRankPageRank
PageRank is a link analysis algorithm, named after Larry Page and used by the Google Internet search engine, that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of "measuring" its relative importance within the set...
. In addition, the Yahoo and Bing search engines also respect this attribute value.
On June 15, 2009, Matt Cutts
Matt Cutts
Matt Cutts works for the Search Quality group in Google, specializing in search engine optimization issues. In an interview with USA Today in June 2008, Cutts provided advice on how to optimize search results on Google.-Career:...
, a well-known software engineer of Google, announced on his blog that GoogleBot will no longer treat nofollowed links in the same way, in order to prevent webmasters from using nofollow for PageRank sculpting. As a result of this change the usage of nofollow leads to evaporation of pagerank. In order to avoid the above, SEOs developed alternative techniques that replace nofollowed tags with obfuscated JavaScript code and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and JavaScript.
Interpretation by the individual search engines
While all engines that use thenofollow value exclude links that use it from their ranking calculation, the details about the exact interpretation of it vary from search engine to search engine.- GoogleGoogleGoogle Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
states that their engine takes "nofollow" literally and does not "follow" the link at all. However, experiments conducted by SEOsSearch engine optimizationSearch engine optimization is the process of improving the visibility of a website or a web page in search engines via the "natural" or un-paid search results...
show conflicting results. These studies reveal that Google does follow the link, but it does not index the linked-to page, unless it was in Google's index already for other reasons (such as other, non-nofollow links that point to the page). - Yahoo!Yahoo!Yahoo! Inc. is an American multinational internet corporation headquartered in Sunnyvale, California, United States. The company is perhaps best known for its web portal, search engine , Yahoo! Directory, Yahoo! Mail, Yahoo! News, Yahoo! Groups, Yahoo! Answers, advertising, online mapping ,...
"follows it", but excludes it from their ranking calculation. - Bing respects "nofollow" as regards not counting the link in their ranking, but it is not proven whether or not Bing follows the link.
- Ask.comAsk.comAsk is a Q&A focused search engine founded in 1996 by Garrett Gruener and David Warthen in Berkeley, California. The original software was implemented by Gary Chevsky from his own design. Warthen, Chevsky, Justin Grant, and others built the early AskJeeves.com website around that core engine...
also respects the attribute.
| rel="nofollow" Action | Yahoo | Bing | Ask.com | |
|---|---|---|---|---|
| Uses the link for ranking | No | No | No | ? |
| Follows the link | No | Yes | ? | No |
| Indexes the "linked to" page | No | Yes | No | No |
| Shows the existence of the link | Only for a previously indexed page | Yes | Yes | Yes |
| In results pages for anchor text | Only for a previously indexed page | Yes | Only for a previously indexed page | Yes |
Use by weblog software
Most weblog software marks reader-submitted links this way by default (with no option to disable it, except for modification of the software's code).More sophisticated server software could spare the nofollow for links submitted by trusted users
Trust metric
In psychology and sociology, a trust metric is a measurement of the degree to which one social actor trusts another social actor...
like those registered for a long time, on a whitelist, or with an acceptable karma level. Some server software adds
rel="nofollow" to pages that have been recently edited but omits it from stable pages, under the theory that stable pages will have had offending links removed by human editors.The widely used blogging platform WordPress
WordPress
WordPress is a free and open source blogging tool and publishing platform powered by PHP and MySQL. It is often customized into a content management system . It has many features including a plug-in architecture and a template system. WordPress is used by over 14.7% of Alexa Internet's "top 1...
versions 1.5 and above automatically assign the
nofollow attribute to all user-submitted links (comment data, commenter URI, etc.). However, there are several free plugins available that automatically remove the nofollow attribute value.Use on other websites
MediaWikiMediaWiki
MediaWiki is a popular free web-based wiki software application. Developed by the Wikimedia Foundation, it is used to run all of its projects, including Wikipedia, Wiktionary and Wikinews. Numerous other wikis around the world also use it to power their websites...
software, which powers Wikipedia
Wikipedia
Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...
, was equipped with nofollow support soon after initial announcement in 2005. The option was enabled on most Wikipedias. One of the prominent exceptions was the English Wikipedia
English Wikipedia
The English Wikipedia is the English-language edition of the free online encyclopedia Wikipedia. Founded on 15 January 2001 and reaching three million articles by August 2009, it was the first edition of Wikipedia and remains the largest, with almost three times as many articles as the next...
. Initially, after a discussion, it was decided not to use
rel="nofollow" in articles and to use a URL blacklist instead. In this way, English Wikipedia contributed to the scores of the pages it linked to, and expected editors to link to relevant pages.In May 2006, a patch to MediaWiki software allowed to enable nofollow selectively in namespace
Namespace
In general, a namespace is a container that provides context for the identifiers it holds, and allows the disambiguation of homonym identifiers residing in different namespaces....
s. This functionality was used on pages that are not considered to be part of the actual encyclopedia, such as discussion pages and resources for editors.
nofollow is a value that can be assigned to the
rel attributeRel attribute
A link relation is a descriptive attribute attached to a hyperlink in order to define the type of the link, or the relationship between the source and destination resources. The attribute can be used by automated systems, or can be presented to a user in a different way.In HTML these are designated...
of an HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
a element to instruct some search engineWeb search engine
A web search engine is designed to search for information on the World Wide Web and FTP servers. The search results are generally presented in a list of results often referred to as SERPS, or "search engine results pages". The information may consist of web pages, images, information and other...
s that a hyperlink
Hyperlink
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...
should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing
Spamdexing
In computing, spamdexing is the deliberate manipulation of search engine indexes...
from occurring.
Concept and specification
Thenofollow value was originally suggested to stop comment spam in blogsSpam in blogs
Spam in blogs is a form of spamdexing. It is done by automatically posting random comments or promoting commercial services to blogs, wikis, guestbooks, or other publicly...
. Believing that comment spam affected the entire blogging community, in early 2005 Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
’s Matt Cutts
Matt Cutts
Matt Cutts works for the Search Quality group in Google, specializing in search engine optimization issues. In an interview with USA Today in June 2008, Cutts provided advice on how to optimize search results on Google.-Career:...
and Blogger
Blogger (service)
Blogger is a blog-publishing service that allows private or multi-user blogs with time-stamped entries. It was created by Pyra Labs, which was bought by Google in 2003. Generally, the blogs are hosted by Google at a subdomain of blogspot.com. Up until May 1, 2010 Blogger allowed users to publish...
’s Jason Shellen proposed the value to address the problem.
The specification for
nofollow is copyrighted 2005-2007 by the authors and subject to a royalty free patent policy, e.g. per the W3C Patent Policy 20040205,W3C Patent Policy 20040205,W3.ORG and IETF RFC 3667 & RFC 3668. The authors intend to submit this specification to a standards body with a liberal copyright/licensing policy such as the GMPGGMPG
GMPG or Global Multimedia Protocols Group is an informal organization who engages in experiments in Metamemetics.It was first mentioned in 1992 by author Neal Stephenson in his novel Snow Crash....
, IETF, and/or W3C.
Introduction and support
GoogleGoogle
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
announced in early 2005 that hyperlinks with
rel="nofollow"W3C (December 24, 1999), HTML 4.01 Specification, W3C.org, retrieved May 29, 2007 would not influence the link target's PageRankPageRank
PageRank is a link analysis algorithm, named after Larry Page and used by the Google Internet search engine, that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of "measuring" its relative importance within the set...
.Google (January 18, 2006), Preventing comment spam, Official Google Blog, retrieved on May 29, 2007 In addition, the Yahoo and Bing search engines also respect this attribute value.Microsoft (June 3, 2008), Bing.com, "Bing Community", retrieved on June 11, 2009
On June 15, 2009, Matt Cutts
Matt Cutts
Matt Cutts works for the Search Quality group in Google, specializing in search engine optimization issues. In an interview with USA Today in June 2008, Cutts provided advice on how to optimize search results on Google.-Career:...
, a well-known software engineer of Google, announced on his blog that GoogleBot will no longer treat nofollowed links in the same way, in order to prevent webmasters from using nofollow for PageRank sculpting. As a result of this change the usage of nofollow leads to evaporation of pagerank. In order to avoid the above, SEOs developed alternative techniques that replace nofollowed tags with obfuscated JavaScript code and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and JavaScript.
Interpretation by the individual search engines
While all engines that use thenofollow value exclude links that use it from their ranking calculation, the details about the exact interpretation of it vary from search engine to search engine.Loren Baker (April 29, 2007),How Google, Yahoo & Ask.com Treat the No Follow Link Attribute, Search Engine Journal, retrieved May 29, 2007- GoogleGoogleGoogle Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
states that their engine takes "nofollow" literally and does not "follow" the link at all. However, experiments conducted by SEOsSearch engine optimizationSearch engine optimization is the process of improving the visibility of a website or a web page in search engines via the "natural" or un-paid search results...
show conflicting results. These studies reveal that Google does follow the link, but it does not index the linked-to page, unless it was in Google's index already for other reasons (such as other, non-nofollow links that point to the page). - Yahoo!Yahoo!Yahoo! Inc. is an American multinational internet corporation headquartered in Sunnyvale, California, United States. The company is perhaps best known for its web portal, search engine , Yahoo! Directory, Yahoo! Mail, Yahoo! News, Yahoo! Groups, Yahoo! Answers, advertising, online mapping ,...
"follows it", but excludes it from their ranking calculation. - Bing respects "nofollow" as regards not counting the link in their ranking, but it is not proven whether or not Bing follows the link.
- Ask.comAsk.comAsk is a Q&A focused search engine founded in 1996 by Garrett Gruener and David Warthen in Berkeley, California. The original software was implemented by Gary Chevsky from his own design. Warthen, Chevsky, Justin Grant, and others built the early AskJeeves.com website around that core engine...
also respects the attribute.http://about.ask.com/en/docs/about/webmasters.shtml#10
| rel="nofollow" Action | Yahoo | Bing | Ask.com | |
|---|---|---|---|---|
| Uses the link for ranking | No | No | No | ? |
| Follows the link | No | Yes | ? | No |
| Indexes the "linked to" page | No | Yes | No | No |
| Shows the existence of the link | Only for a previously indexed page | Yes | Yes | Yes |
| In results pages for anchor text | Only for a previously indexed page | Yes | Only for a previously indexed page | Yes |
Use by weblog software
Most weblog software marks reader-submitted links this wayGoogle Blog (January 18, 2005), http://googleblog.blogspot.com/2005/01/preventing-comment-spam.html, The Official Google Blog, retrieved September 28, 2010 by default (with no option to disable it, except for modification of the software's code).More sophisticated server software could spare the nofollow for links submitted by trusted users
Trust metric
In psychology and sociology, a trust metric is a measurement of the degree to which one social actor trusts another social actor...
like those registered for a long time, on a whitelist, or with an acceptable karma level. Some server software adds
rel="nofollow" to pages that have been recently edited but omits it from stable pages, under the theory that stable pages will have had offending links removed by human editors.The widely used blogging platform WordPress
WordPress
WordPress is a free and open source blogging tool and publishing platform powered by PHP and MySQL. It is often customized into a content management system . It has many features including a plug-in architecture and a template system. WordPress is used by over 14.7% of Alexa Internet's "top 1...
versions 1.5 and above automatically assign the
nofollow attribute to all user-submitted links (comment data, commenter URI, etc.).Codex Documentation, Nofollow, Wordpress.org Documentation, retrieved May 29, 2007 However, there are several free plugins available that automatically remove the nofollow attribute value.WordPress Plugins, Plugins tagged as Nofollow, WordPress Extensions, retrieved March 10, 2008Use on other websites
MediaWikiMediaWiki
MediaWiki is a popular free web-based wiki software application. Developed by the Wikimedia Foundation, it is used to run all of its projects, including Wikipedia, Wiktionary and Wikinews. Numerous other wikis around the world also use it to power their websites...
software, which powers Wikipedia
Wikipedia
Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...
, was equipped with nofollow support soon after initial announcement in 2005. The option was enabled on most Wikipedias. One of the prominent exceptions was the English Wikipedia
English Wikipedia
The English Wikipedia is the English-language edition of the free online encyclopedia Wikipedia. Founded on 15 January 2001 and reaching three million articles by August 2009, it was the first edition of Wikipedia and remains the largest, with almost three times as many articles as the next...
. Initially, after a discussion, it was decided not to use
rel="nofollow" in articles and to use a URL blacklist instead. In this way, English Wikipedia contributed to the scores of the pages it linked to, and expected editors to link to relevant pages.In May 2006, a patch to MediaWiki software allowed to enable nofollow selectively in namespace
Namespace
In general, a namespace is a container that provides context for the identifiers it holds, and allows the disambiguation of homonym identifiers residing in different namespaces....
s. This functionality was used on pages that are not considered to be part of the actual encyclopedia, such as discussion pages and resources for editors.
nofollow is a value that can be assigned to the
rel attributeRel attribute
A link relation is a descriptive attribute attached to a hyperlink in order to define the type of the link, or the relationship between the source and destination resources. The attribute can be used by automated systems, or can be presented to a user in a different way.In HTML these are designated...
of an HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
a element to instruct some search engineWeb search engine
A web search engine is designed to search for information on the World Wide Web and FTP servers. The search results are generally presented in a list of results often referred to as SERPS, or "search engine results pages". The information may consist of web pages, images, information and other...
s that a hyperlink
Hyperlink
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...
should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing
Spamdexing
In computing, spamdexing is the deliberate manipulation of search engine indexes...
from occurring.
Concept and specification
Thenofollow value was originally suggested to stop comment spam in blogsSpam in blogs
Spam in blogs is a form of spamdexing. It is done by automatically posting random comments or promoting commercial services to blogs, wikis, guestbooks, or other publicly...
. Believing that comment spam affected the entire blogging community, in early 2005 Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
’s Matt Cutts
Matt Cutts
Matt Cutts works for the Search Quality group in Google, specializing in search engine optimization issues. In an interview with USA Today in June 2008, Cutts provided advice on how to optimize search results on Google.-Career:...
and Blogger
Blogger (service)
Blogger is a blog-publishing service that allows private or multi-user blogs with time-stamped entries. It was created by Pyra Labs, which was bought by Google in 2003. Generally, the blogs are hosted by Google at a subdomain of blogspot.com. Up until May 1, 2010 Blogger allowed users to publish...
’s Jason Shellen proposed the value to address the problem.
The specification for
nofollow is copyrighted 2005-2007 by the authors and subject to a royalty free patent policy, e.g. per the W3C Patent Policy 20040205,W3C Patent Policy 20040205,W3.ORG and IETF RFC 3667 & RFC 3668. The authors intend to submit this specification to a standards body with a liberal copyright/licensing policy such as the GMPGGMPG
GMPG or Global Multimedia Protocols Group is an informal organization who engages in experiments in Metamemetics.It was first mentioned in 1992 by author Neal Stephenson in his novel Snow Crash....
, IETF, and/or W3C.
Introduction and support
GoogleGoogle
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
announced in early 2005 that hyperlinks with
rel="nofollow"W3C (December 24, 1999), HTML 4.01 Specification, W3C.org, retrieved May 29, 2007 would not influence the link target's PageRankPageRank
PageRank is a link analysis algorithm, named after Larry Page and used by the Google Internet search engine, that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of "measuring" its relative importance within the set...
.Google (January 18, 2006), Preventing comment spam, Official Google Blog, retrieved on May 29, 2007 In addition, the Yahoo and Bing search engines also respect this attribute value.Microsoft (June 3, 2008), Bing.com, "Bing Community", retrieved on June 11, 2009
On June 15, 2009, Matt Cutts
Matt Cutts
Matt Cutts works for the Search Quality group in Google, specializing in search engine optimization issues. In an interview with USA Today in June 2008, Cutts provided advice on how to optimize search results on Google.-Career:...
, a well-known software engineer of Google, announced on his blog that GoogleBot will no longer treat nofollowed links in the same way, in order to prevent webmasters from using nofollow for PageRank sculpting. As a result of this change the usage of nofollow leads to evaporation of pagerank. In order to avoid the above, SEOs developed alternative techniques that replace nofollowed tags with obfuscated JavaScript code and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and JavaScript.
Interpretation by the individual search engines
While all engines that use thenofollow value exclude links that use it from their ranking calculation, the details about the exact interpretation of it vary from search engine to search engine.Loren Baker (April 29, 2007),How Google, Yahoo & Ask.com Treat the No Follow Link Attribute, Search Engine Journal, retrieved May 29, 2007- GoogleGoogleGoogle Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
states that their engine takes "nofollow" literally and does not "follow" the link at all. However, experiments conducted by SEOsSearch engine optimizationSearch engine optimization is the process of improving the visibility of a website or a web page in search engines via the "natural" or un-paid search results...
show conflicting results. These studies reveal that Google does follow the link, but it does not index the linked-to page, unless it was in Google's index already for other reasons (such as other, non-nofollow links that point to the page). - Yahoo!Yahoo!Yahoo! Inc. is an American multinational internet corporation headquartered in Sunnyvale, California, United States. The company is perhaps best known for its web portal, search engine , Yahoo! Directory, Yahoo! Mail, Yahoo! News, Yahoo! Groups, Yahoo! Answers, advertising, online mapping ,...
"follows it", but excludes it from their ranking calculation. - Bing respects "nofollow" as regards not counting the link in their ranking, but it is not proven whether or not Bing follows the link.
- Ask.comAsk.comAsk is a Q&A focused search engine founded in 1996 by Garrett Gruener and David Warthen in Berkeley, California. The original software was implemented by Gary Chevsky from his own design. Warthen, Chevsky, Justin Grant, and others built the early AskJeeves.com website around that core engine...
also respects the attribute.http://about.ask.com/en/docs/about/webmasters.shtml#10
| rel="nofollow" Action | Yahoo | Bing | Ask.com | |
|---|---|---|---|---|
| Uses the link for ranking | No | No | No | ? |
| Follows the link | No | Yes | ? | No |
| Indexes the "linked to" page | No | Yes | No | No |
| Shows the existence of the link | Only for a previously indexed page | Yes | Yes | Yes |
| In results pages for anchor text | Only for a previously indexed page | Yes | Only for a previously indexed page | Yes |
Use by weblog software
Most weblog software marks reader-submitted links this wayGoogle Blog (January 18, 2005), http://googleblog.blogspot.com/2005/01/preventing-comment-spam.html, The Official Google Blog, retrieved September 28, 2010 by default (with no option to disable it, except for modification of the software's code).More sophisticated server software could spare the nofollow for links submitted by trusted users
Trust metric
In psychology and sociology, a trust metric is a measurement of the degree to which one social actor trusts another social actor...
like those registered for a long time, on a whitelist, or with an acceptable karma level. Some server software adds
rel="nofollow" to pages that have been recently edited but omits it from stable pages, under the theory that stable pages will have had offending links removed by human editors.The widely used blogging platform WordPress
WordPress
WordPress is a free and open source blogging tool and publishing platform powered by PHP and MySQL. It is often customized into a content management system . It has many features including a plug-in architecture and a template system. WordPress is used by over 14.7% of Alexa Internet's "top 1...
versions 1.5 and above automatically assign the
nofollow attribute to all user-submitted links (comment data, commenter URI, etc.).Codex Documentation, Nofollow, Wordpress.org Documentation, retrieved May 29, 2007 However, there are several free plugins available that automatically remove the nofollow attribute value.WordPress Plugins, Plugins tagged as Nofollow, WordPress Extensions, retrieved March 10, 2008Use on other websites
MediaWikiMediaWiki
MediaWiki is a popular free web-based wiki software application. Developed by the Wikimedia Foundation, it is used to run all of its projects, including Wikipedia, Wiktionary and Wikinews. Numerous other wikis around the world also use it to power their websites...
software, which powers Wikipedia
Wikipedia
Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...
, was equipped with nofollow support soon after initial announcement in 2005. The option was enabled on most Wikipedias. One of the prominent exceptions was the English Wikipedia
English Wikipedia
The English Wikipedia is the English-language edition of the free online encyclopedia Wikipedia. Founded on 15 January 2001 and reaching three million articles by August 2009, it was the first edition of Wikipedia and remains the largest, with almost three times as many articles as the next...
. Initially, after a discussion, it was decided not to use
rel="nofollow" in articles and to use a URL blacklist instead. In this way, English Wikipedia contributed to the scores of the pages it linked to, and expected editors to link to relevant pages.In May 2006, a patch to MediaWiki software allowed to enable nofollow selectively in namespace
Namespace
In general, a namespace is a container that provides context for the identifiers it holds, and allows the disambiguation of homonym identifiers residing in different namespaces....
s. This functionality was used on pages that are not considered to be part of the actual encyclopedia, such as discussion pages and resources for editors.Wikipedia (May 29, 2006),