rainborick - 6:16 pm on Feb 14, 2008 (gmt 0)
Officially, Yahoo! and MSN Live are both supposed to be on board with rel=nofollow - that is, links with that attribute will not be used for ranking purposes. All three made an announcement about their combined support, at or closely following some SEM convention, as a means of combating BLOG comment SPAM. While the reasons for using it have expanded, I haven't seen any of them announce withdrawing their support. The differences in support should be limited to those fringe details like whether or not their individual crawlers actually follow such links. Like most people, I'm not so worried about how Yahoo! and MSN deal with it. What I've seen from Google's behavior is that whatever else they may or may not do with nofollow'ed links - it looks to me that, as promised, they don't pass link juice, and further that nofollow'ed links don't count as links in how the PageRank passed by the normal links on the same page.