Have you ever gone to one of those rubber chicken dinners, the kind where there are 10-person tables scattered around a ballroom with weirdly patterned carpeting? Sometimes there is a speaker trying to make a presentation while the silverware clinks and waiters refill the water glasses. Kinda uncomfortable and boring, right? That's the way some online communities are set up...too formal and restrictive, with bland, pre--packaged topics presented by a lone host. Not the kind of place you want to hang around.
Some communities go to the opposite end of the spectrum...a full-on toga keg party, where anything goes and people wake up the next day with regrets and headaches. Participants post things they shouldn't, and short of "calling the cops," there's no way to get it under control.
Middle ground might be a kid's birthday party with a bouncy house. The parents are there to make sure no-one gets hurt, but fun is had by all, and everyone goes home with a goodie bag and sugar high. You need to watch out that the "cool kids" don't exclude the new guy, and that the class troublemaker doesn't release all the balloons, but it's generally a good time. The question is, do you want to go there every day? Maybe not.
How about this scenario---it's a dinner party thrown by very close friends. It's friendly, casual, and you feel free to go beyond "cocktail party" conversation. The hosts have prepared your favorite foods, the home is cozy and inviting, and there is an interesting mixture of guests. Some of you already know each other, but you're open to meeting the new neighbors who've been invited. Everyone ends the evening lounging on the patio around the firepit, telling stories and laughing. Hey, I'm ready to go there now!
Ultimately, even if your online community exists to support your business or marketing goals, you need to give thought to the vibe of your party. Don't be throwing a rubber chicken dinner; gather your friends.