If you keep a blog, this is important. You should read it and take heed. If you use Typepad or LiveJournal, you’re covered (or will be soon). If you use Movable Type, see this post. If you use Blogger or Blogspot… um, I dunno, but since it’s a Google initiative and Blogger/Blogspot is owned by Google, I imagine support will come pretty quickly.
Now, this isn’t going to stop spammers from spitting out comments all over your blog. It will make them less likely to benefit from those comments. It would be nice to think that less benefit means less spam, but let’s be serious — the people selling the software that generates this spam aren’t going to tell their customers that it’s a worthless activity. Still, you’re cutting back on whatever money spammers are making, and that’s a good enough reason to do it in my book.