As Dominique pointed out, it is actually what you are excited about works the best for you. Some prefer poker more than casino, most hate doing bingo. But there are affiliates who do very well promoting bingo. It’s all about what you are passionate about.
The stickyness and average yield per casino player is way ahead than that of a poker or sports book player. And promoting poker or sportsbook is a volumes game. If this makes sense :bigsmile:
Over all if you look at the industry an affiliate site will make more money than a affiliate forum, coz of the nature of the objectives of both ventures. Affiliate Forums are community sites with the main objective of sharing knowledge and experience, resolving issues and helping each other. This doesn’t mean the forums make less 
However compared to sites like casino.com, yes.
Cheers
Satya