As far as Bitcointalk specifically - we just joined the yesterday, but we're already planning lots of specific promotions that will only be available here to forum users!
This is good to hear since great sportsbook promotions are usually what attract me easily since I am an avid sports betting punter myself. Rakeback offer applies to the casino games, but what about sports betting cashback?
An offer like cashback on lost bets or cashback on a certain amount of wagers would be quite attractive in my opinion. Keep improving team.