Your offer is really tempting but people are so skeptical due to your reputation so maybe try different approach since people nowadays doesn't want to spend time on things that they now risky or not worth it. So try to listen the sentiments of people since if you are serious to promote your forum here then you must do something and apply those people suggestion or create another action base on the approach you have read.

Creating a platform like this is not so easy since you need to have a lot of money to market your site and convince those people to stay then have a discussion on each boards in your forum.

Good luck for this and we hope to see something great to happen especially on the marketing you plan to do.