Have you ever heard an anthem that sings about members of that country's population before? Like I said, I'd suggest singing about Eyes on Final Fantasy. You can say 'members' when referring to the people within. I guess when I think "anthem" I think "song about the place the people go to" rather than "song about the people" =]

You could sing about the elections, the Ciddies, Eyes on YOU, Cid, the various forums, the frontsite, the chatroom, the atmosphere, the community... loads of things!