One of the forums I've been on before, the owner felt the need to constantly pay to get people to join, even if it meant forking out all of his disposable income, if it meant he got people to join and be active eventually without paid content. In the end, nearly all of the people who joined up because of pay, left. This same forum, also had overzealous moderation. While that in itself isn't bad if you want to make sure people you pay, are contributing quality, it also distracts from the purpose of the end goal, and people who aren't there to get paid from the paid posting, will end up getting penalized because all the moderators see, is content they think is low quality, without considering context.
By all means, run a forum how you like, but I don't want to be on a forum that doesn't have moderators that knows the difference between someone looking to get paid for what they post, and someone that genuinely wants to chat with people for no purpose other than to enjoy being around people who wants to contribute.
I wasted countless hours trying to drill in to the brains of these people that harsh moderation isn't what was needed, and actually looking into where things are posted and it's context, was much better for moderation. In the end, the main culprits of this overbearing moderation, refused to care enough to take what I was trying to drill in moderation practices, as legitimate help.