I'm not going to vote:
I have no idea currently of what the costs of expense, or time to maintain is. So far, from me, it is, effectively, 0. :s.
I do think, generally speaking, there is little activity on these forums, yes.
I would suggest, considering creating something like a 5D subreddit, that could be an alternative, I think it is free.
I don't facebook or tweet tbh, so no interest in a 5D environment on there personally.