The teams can and hopefully will be active before then... it's up to the members of the team of course. Remember you can do anything in those communities - socialize and whatnot!
HOWEVER if you happen to pimp and someone says you suggested it or of an ad in another community is what brought them here, 5 points will be rewarded to the team whose members posted the pimps. This will go towards the First Battle.
So go forth and pimp the community!