I have seen some pretty advance forums which let users share video, photos, music, blogs, and other stuff from their forum profile page. Some Forums also have a comment area on member profiles which is similar to a Wall in Facebook.
I think in general, newer forums with a lot of mods kind of feel like social networks in the forum member profile pages.
I mostly dislike how Social Networks recommend who I should be friends with, what groups I would like, what apps to use on Social Networks, and where to buy my stuff from, and what's popular or not in popular culture.