Post4Host doesn't bring revenue by itself either, unless you show ads on the forum and get people to display and click them.
I've often found post-4-host/features environments feel pretty contrived, even if you forbid one-liners and pointless posts there'll be a part of the crowd that'll be there just to do their minimum "effort" and it feels.
I've been on 110mb.com for a while, they're going the partly "post4features or paid upgrades" way and gosh how crappy the forums have tended to become those last weeks :/ Droves of people asking questions or speculating about stuff that's pointedly answered in the OP or next few posts, necromancy of threads no-one gives a dead horse's --- about any longer, copy-pastes of content from somewhere else out of the blue... yeargh...