You do most of the talking on feeds now, so not a lot of us visit the forums anymore. Visit some random profiles and strike up a conversation. Some kind of stick to their own little group of friends, but there are some who're welcoming of strangers stumbling upon their profiles without freaking out like "omg, why would a stranger talk to me on a social site!"
I think forums should be used more for longer discussions, as it makes them way easier - for example "wall of text" ones. Sadly there's a lot of interesting discussions happening on feeds where only a few get to take part, which would be way better having on the forums so everyone could join in. But even then, you easily get discouraged posting with the "super chill" attitude against nonsense in place, which easily leaves your effort filled posts buried in crap and "troll! bait!" posts.
Moving topics that were successful on the feeds to the forums is hard, as the first posts are lost in the process and you have to start all over again, and few feel like repeating themselves. A feature which could turn feed stories into a forum threads if they meet a certain criteria is something that could be introduced.