Reading between the lines (which in this case isn’t particularly hard), this and this (don’t forget to view source) suggest that 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.
As an aside, I have exams starting in a week and plenty to revise, so I’ll probably be on hiatus until the end of the month.