Tuesday, January 18, 2005 Preventing comment spam
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.