I have been looking forward to that for quite some time. It seems that, at last, Google is about to provide a quick fix to reduce link spam, which will eventually (but not for sure and certainly not overnight) remove the incentive from blog comment spamming. Evidence at Simon Willison's, Dave Winer's and Winer's again. Simon cracks Winer's teasers:
Google are soon to announce that they won't be calculating PageRank for links with a rel="nofollow" attribute. Finally, an official way of fighting the economics of comment spam by denying PageRank on user-submitted link content. Sam Ruby points to Mark Pilgrim's prediction that spammers won't care - they'll spam anyway, on the offchance that they hit somewhere undefended. I'm optimistic - if the major weblog (and wiki) vendors get behind this one it could help stem the tide.
Peter Van Dijck thinks that Google will simply not follow links tagged this way. I agree with him that this is semantically more correct, and I'd rather to see this behavior.
Let's hope that Yahoo! follows suit.
On the other hand, coincidentally, I ran today on worrying reports of long-standing bugs in Google's PageRank that allow spammers to highjack sites PR with a simple redirect. Not pretty. Jeremy Zawodny may be right when saying that PageRank is broken.