As I've lamented here several times, comment spam is a problem. It's encouraging to see steps being taken by major players to combat comment spamming, using an HTML "nofollow" tag that tells search engines not to consider those links. Spammers have traditionally benefited by having links to their sites appear in numerous blogs, and without the search engines indexing and counting those links, the motivation to "publish" the comment spam is, theoretically, diminished.
Hopefully it works half as well in practice as it does in theory. Time will tell.
For more info from Six Apart, click here.
PS I learned while writing this post that the past tense of benefit can be spelled benefitted or benefited.