Getting people to join

I saw a handy little reward system on another site that encouraged players to invite others. When they are signing up for the server (making an account) there is a little box that says: "Who told you about this site". This information is sent to the admin and he then rewards the person who's name is there. I dunno but for us I guess it could be like 50 gp or something.

Just an idea. I hav no clue if it would work, or how much it would be abused, but it seems like a pretty cool system.

It wuld be more interesting if you could actualy get something cool with the GP >_<