No need to join a division, poke your head into wherever you want, whenver you like - save the admin and officers' forums of course
Active members would be hard to enumerate. My own division, 2142, has about 150-200 active members. The community itself has over 25000 registered memebers. Wherever you go there'll be people there.
I can't answer that server question, sorry. 2142 runs two servers atm - one handled by the division, one provided privately by Pahkiller (sorry for that mistake before!) As to other divisions I really have no idea. Perhaps someone else can add more info here.
Members are not required to donate. If you do decide to though, there are other contributions you can make besides money. Graphics, webdesign, or just time and effort. But all that's up to you.
Teamspeak- or Ventrilo - is not compulsory, but to enjoy your time with us, to get to know your fellow TOGgers, and to really join in the fun, it's recommended. Depending on the game, of course. Keeping active int he forums is also encouraged
TOG play almost everything there is, and almost every division will have some sort of competitive team. The BF2 dision used to run three at once.
Members are encouraged to participate and help organise games, etc. That's the way to become a squad leader like myself (I run the 2142 comp team) Forum mods are also promoted from within our own ranks, the admin too, and we use internal talent for graphics and coding etc where we can.
Those are some detailed questions, man
EDIT: Beaten! Leevers u spammer!
Oh, and if you're only 24, sorry. As Leevers noted, we hold to that stronger than just about anything else. When you do turn 25 we'd love you to re-apply