Refer a friend to Planetside 2 via e-mail. When you friend use your e-mail link to sign-up and get to battle rank 15-20+, you are rewarded with 50-100 certs. This promotes players to recruit more new blood. And not very exploitable unless you want to keep creating accounts to get the battle rank 15-20 which will take numerous hours and you would have earned 50-100 certs on your own account if you played on it instead.
It's a good idea to have a refer-a-friend-program that gives some decent rewards. Just make sure people can't exploit it (something like what OP described) and there you go. It really does work and bring some extra players.
