This is entirely wrong. From personal experience, I've seen one of our forums for a utility app, grow a nice little community with not so much as a single false post. Users started appearing by themselves after having tried out the app, and we ended up with a decent, albeit small community on the forum. There's plenty of other forums as well, that grows from a small group of real users. Hell, every subreddit starts like that, except apparently for the first ones populated only by the reddit founders.