I'm super pleased about a new weapon against comment spammers. The top search engines including Google, Yahoo, and MSN, will ignore links that have the rel="nofollow" attribute set. Thanks to a plug-in from Movable Type (the maker of my blog software), this tag gets added to all of the URLs in the comments and trackbacks that people post. If the search engines ignore those links, there will be way less incentive for comment spammers to do their nasty deeds since their links will not increase their page rank.
Nice to see the industry doing something good together without a ton of bureaucracy and worries over IP.
Thanks to Scoble for pointing this out.
(Also, I should note that although Movable Type only tested the plug-in on MT 2.664 and above, it appears to work fine on my 2.64 installation.)