have it so the player can invite up to (10) or (5) friends depending on how many beta keys u want to give a person through Ref link/email/skype. A player will only be tagged as an "invited friend"<to the inviter when he sees them and memorizes them this can change. when he/she creates a new account after using a referral link. The invited player will receive a starter pack (which might include) lower end inspirationals axe and mabeh a hat or somthing, along with a bonus that allows him/her to get Faster skillup's for the first day of play time just a idea might be somthing to add and the refer gets.. like ref points he can spend in a store @ town which would award a cape of referal or something cosmetic
just a idea please go easy on me.
also a thought if the refered player buys some coins or somthing from the real money store the ref should get more "referral points"
if u have somthing to add please post here