If you're a blogger (or a blog reader), you're painfully familiar with people who try to raise their own websites' search engine rankings by submitting linked blog comments like "Visit my discount pharmaceuticals site." This is called comment spam, we don't like it either, and we've been testing a new tag that blocks it. From now on, when Google sees the attribute (rel="nofollow") on hyperlinks, those links won't get any credit when we rank websites in our search results. This isn't a negative vote for the site where the comment was posted; it's just a way to make sure that spammers get no benefit from abusing public areas like blog comments, trackbacks, and referrer lists.
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If you're a blogger (or a blog reader), you're painfully familiar with people who try to raise their own websites' search engine rankings by submitting linked blog comments like "Visit my discount pharmaceuticals site." This is called comment spam, we don't like it either, and we've been testing a new tag that blocks it. From now on, when Google sees the attribute (rel="nofollow") on hyperlinks, those links won't get any credit when we rank websites in our search results. This isn't a negative vote for the site where the comment was posted; it's just a way to make sure that spammers get no benefit from abusing public areas like blog comments, trackbacks, and referrer lists.
We hope the web software community will quickly adopt this attribute and we're pleased that a number of blog software makers have already signed on:
Brad Fitzpatrick -
LiveJournalDave Winer -
Scripting NewsAnil Dash -
Six ApartSteve Jenson -
BloggerMatt Mullenweg -
WordPressStewart Butterfield -
FlickrAnthony Batt -
BuzznetDavid Czarnecki -
blojsomRael Dornfest -
BlosxomMike Torres -
MSN SpacesWe've also discussed this issue with colleagues at our fellow search engines and would like to thank
MSN Search and
Yahoo! for supporting this initiative. Here are a few guidelines for anyone else who wants to join the cause.
Q: How does a link change?A: Any link that a user can create on your site automatically gets a new "nofollow" attribute. So if a blog spammer previously added a comment like
Visit my <a href="http://www.example.com/">discount pharmaceuticals</a> site.
That comment would be transformed to
Visit my <a href="http://www.example.com/" rel="nofollow">discount pharmaceuticals</a> site.
Q: What types of links should get this attribute?A: We encourage you to use the rel="nofollow" attribute anywhere that users can add links by themselves, including within comments, trackbacks, and referrer lists. Comment areas receive the most attention, but securing every location where someone can add a link is the way to keep spammers at bay.
Q: Should I put rel="nofollow" on the link to my comments page?A: Probably not, because lots of interesting discussion can happen there. Also, if other people link to your comments page, a spider can follow that link and find any spam that's lurking on the comments page.
The best places to add this attribute are the actual links that other people can create. So on
this page, for instance, only the links within comments and the link immediately after "Posted by:" would get the rel="nofollow" attribute.
Q: Do individual bloggers need to do anything?A: Probably not. Updating the software that generates these pages will ensure that most bloggers get these changes automatically.
Q: Is this a blog-only change?A: No. We think any piece of software that allows others to add links to an author's site (including guestbooks, visitor stats, or referrer lists) can use this attribute. We're working primarily with blog software makers for now because blogs are such a common target.
Got more questions? Email commentspam at google.com. As we spot more areas where spammers still abuse the Web, we'll contact the appropriate people in order to keep fighting comment spam.
Matt Cutts, Google Software Engineer
Jason Shellen, Blogger Program Manager
Update: The reaction to nofollow has really been quite positive, especially considering how diverse the web is. We're delighted to announce more support for nofollow:
Ross Rader -
BlogwareJohn Panzer -
AOL JournalsKevin Marks - of
Technorati also added a
draft formal spec for nofollow.
Reini Urban -
PhpWikiDavid Gorman -
ModBlogArnab Nandi -
DrupalJames Tauber -
LeonardoJeremie Bouillon - points out a
GPL plugin for
TextpatternSimon Brown -
PebbleIlkka Huotari -
NetdocShaun Inman -
ShortStatEaden McKee -
bBlogYariv Habot -
backBlogJohn Lyons -
enetationSteven Roussey -
Network54Will Yardley -
Dreambook[Update] Samuel Klingen Daams -
TravellerspointWe also wanted to add another question from a reader:
Q: Will Google recognize the 'nofollow' keyword when it's part of a space separated list? According to the HTML spec, the value of the 'rel' attribute is a space separated list of link types.A: Absolutely. We'll practice the "be liberal in what you accept" philosophy, which means recognizing spaces, commas and, in fact, most punctuation. But we strongly recommend using spaces as separators to follow the specification.