You hardly will find post in Blogs and forums these days that will advise you not to bother with sites that are using nofollow tag and to use “DoFollow” (whatever this is) sites only. When I see something like that, I’m instantly know that poster either an idiot who has no idea what he’s talking about or spammer who’s making post count or both.
What nofollow really does and why Google has had come up with this concept? Simple answer is, to inform crawler that there is no need to visit other site thus to spare Google’s crawling time and servers resources and that’s all to it. Google never said that it will disregard backlinks or will give them lesser weight or they won’t help site’s PR, all it wants is no to be hustle needlessly.
So, next time you’ll see some “genius” gives advise to use “dofollow” only, rest assured that he has no idea what he is talking about.