... as for the 'credits':
Every time you post, you get 5 credits. When you start a thread and people reply to your thread you get them as well (don't know how much though, never payed attention).
You might think, well, what's the fun in that?
With those credits, you can start virtual betting (i.e., with virtual cash, = credits) over here: http://www.menstennisforums.com/vbookie.php?
, betting on which player will win a match, set scores, or whatever - and make even more credits, or lose 'em all, if you suck at the bets,
Might not mean anything, just for fun, but I've personally experienced that at times, a completely meaningless match between two players which you don't care about at all, but on which match you've put on a lot of vCash (= credits) suddenly becomes very interesting...