Looking at your post history, you have mentioned this site several times already. Are you promoting it as player or you are one of their team members?
Frankly speaking, it is the first time I heard about bitbook. I just did quick visit on the main site and I can say that it is just another casino sites that provides games from some various gaming providers and sports betting. Most of the games are slot games which has high house edge, so I do not think that they only take small cuts from the games unless you are talking about the sports betting.