Ask YC: forums still a viable format (group-enemy problem)?

I have a hypothesis: forums still exist and are still popular, despite being (feature and ux-wise) stuck in the 2000s. The 1 issue they could never solve is the "a group is its own worst enemy" problem, which Twitter addresses with the follow mechanism, Facebook addresses with the friend mechanism, answer sites by structing the discussion as an "answer", yc and co with upvoting etc. Forums rock though by bringing people together around topics, I don't think social networks/twitter/blogs/... compete with them there.<p>My hypothesis is this: forums can stand their own against social networks/blogs/... etc, but they have to be able to definitively solve the group-enemy problem.<p>Thoughts?