Do you miss something on BrainKing.com and would you like to see it here? Post your request into this board! If there is a more specific board for the request, (i.e. game rule changes etc) then it should be posted and discussed on that specific board.
Fellowships - For the most part, they are a group of people with a similar interest. Take for example my Backgammon fellowship, called The Gammon Cube. What you would find there if you joined was a group of other people that is also interested in (back)gammon games. I host montly tournaments just for the fellowship members. Also included is a discussion board that can only be accessed by members of the fellowship. Also if you wanted, you could join a team. Teams don't do much right now, but some day the teams will be able to have challenge matches with other fellowship teams.
A fellowship like the debate club, and some others are mostly there just for the discussion board only. (I think the debate club had a fun backgammon tournament you can join, but it is mostly just for the private discussion board.)
ALSO, you can leave at any time. So feel free to check some fellowships out. If you find you don't like them, you can leave at any time.