I'm a forum addict.
I have 9 forums myself and I post on even more forums of other people. I like forums. They're fun and entertaining. They're a lot slower pace than social media which is nice for a change.
How many forums do you run? How many forums are you a member of? I'd guess one of those questions are easy to answer while the other is a sit down and think of the answer.
There are worse things to be addicted to, right?
Forums are great to run and post on as long as you don't get overwhelmed.
6 or my 9 forums are serious, but I have a strategy in place to keep them from overwhelming me.
What's my strategy? What's my secret?
Simple...
I have a life outside of my forums!
That's it.
The guy I'm talking about runs his own like business. He will groom the forums for a while before sell them off and keep buying new ones or start another from a scratch.
You're right about having some other good ways to make money from forums that's not ads. I'm very sure of using partnership and sponsorship as viable options.
You can partner with companies to conduct market research through the forum community using surveys with members participating for incentives for their answers. I've seen Bizdustry do it and it worked.