Let's discuss. Posts exchange good or bad? I personally do some posts exchanges in the past. I would recommend for admin who want to keep the current 'loyal' members active to do posts exchange. However, if you are going to do it because you want your forums to be filled with posts so as to trick new user to sign-up.. Dont try.
There is no benefit - for me - in doing post exchanges.
Here are my issues with post exchanges:
- Posts are usually not good quality at either forum
- You're spending time away from your forum
- You're creating content for someone else and giving up control of your own content
- Little reward for high amount of work
Sure, it may make your forum look busy in the short term, but will not help in the long term. Quality content trumps ANY post exchange.