That no follow tag thing was all a big publicity stunt!
The blog owners out there whined that they had all kinds of people running post bots and filling up their comments with spam - of course anyone of those blog owners could have done some real simple Webmastering and prevented them - well the SEs decided they wanted to look "good" to the public in "their fight against spam" so they agreed to announce they would honor the tag nofollow in links.
The only problem with all of this is that those same whiney cant do anything for themselves blog owners are now going to have to go edit every one of their comment form links
which wont happen and eveyone will still be spammin blogs just as much