Fellow blogger Al Bredenberg forwarded this to me. Hopefully the idea will drastically reduce comment spam on blogs.
GOOGLE MOVES TO OUTSMART SEARCH MANIPULATORS
Google is implementing a new tactic for blocking "link spammers" -- people who use the comment form on Web forums or blogs to place a link pointing back to their own Web site. The strategy is used to trick Google's PageRank technology into boosting a Web site's ranking in its results. The problem has become particularly rampant in the age of blogging, when publishers have little recourse to stop outsiders from littering their comment forms with bogus links. Google's answer, says search expert Danny Sullivan, is to give publishers a "no follow" tag that they can insert on a Web page to indicate that comments or links are not their own and signal Google as it indexes the Web that the pages are to be overlooked.
"The tag provides you a way to flag links that are basically not yours," says Sullivan. "The reason why that's helpful is because they won't count those links. It makes the idea of spamming less attractive." Blog publisher Six Apart says it will adopt the tagging standard for its roughly 6.5 million blogs. "We're interested in deploying this tool so that all the search engines, whether it's Google, Yahoo or MSN, can properly distinguish content published by the author from content from commentors," says Six Apart VP Anil Dash.