All I can say is in the very narrow niche I look at closely, it seems that article posting, blog comments, forum profiles, etc still seem to work equally quite well.
It isn't a hugely competitive niche though.
We have seen ebay, amazon, and ehow move into the top 10 in SERPs. Those sites have tons of inbound links, obviously, but the content is not so much "on topic." And of course, those three aren't running around posting blog comments or user profiles.
I think the thing to do is look at your competitors' links and try and get "better" links than them, whatever their links are.