Before you thank Google (and its competitors, who got an agreement, against all odds — unless they’re still powered by Google these days? I’m not sure), you should note that it’ll benefit them much more than you: the improvement of search accuracy should be visible rather quickly (with a minimum of all Blogger and LiveJournal blogs instantaneously implementing the change), it’ll be much longer before widespread adoption makes comment spam improductive.

You should also note that, if they hadn’t given in to semantically correct, and had created a <div robots="nofollow"> (inside which all links would be ignored), it would have been so much simpler for everyone.