While I missed out on what collab was like. What about having something like a shout box in the forum. This could be linked to a plugin in FL Studio and bring up text like the Download and Library manager. People could post stuff in the shout box or from inside FL with this new plugin if they want to find out stuff. If someone was then helping you, you could then go from the shout box to a more one to one chat. People that come on the forum could still read what you were doing to learn tips from experienced uses but you would also have an option to keep the conversation private.
While this can be done on any instant messaging client, this has the appeal that it's focused towards just writing music. There will always be a forum while FL is going and i'm sure most people will come to the forum when they have something to ask about music. It's got a good chance that it would get used.