Paid posting can very easily come off as vapid and spammy, and this is something to bear in mind especially if you're breaking into a rather strong willed space. It's certainly turned me off in the past. You'd be fortunate to buy your way into a space that thrives on depth if you are paying people to post who do not exude real interest in the subject matter. Even unpaid 'seed threads' built to simply encourage discussion can come off this way. And if you have someone with a genuine passion lured into a paid posting crowd which clearly doesn't know what it's on about and then disappears when the job is done, well then you've made a mess of it and the user may well bring that experience to their other, established spaces. Forums that have really stood the test of time do so because people step into threads produced largely by competent members, whatever the forum's scope... play the long game, or consider another game. If you want to bring value in the space, seek out articles related to how to offer a valuable service to the market you're going into and ensure those offerings are maintained. Something that is worth visiting for even if the forum isn't popping off with constant new threads.