I think, to encourage players to sign up with referral codes, they will get a special fur or shop item or title. The older account can choose which item to give their referees, and when the new player signs up, they will automatically get that item. The older account getting the item as well is optional, unless you think getting 1 cheese of every 10 of their cheese is reward enough. But if the prize is shared by the two accounts, you could add exclusive items that cannot be bought in the shop or won in an event. You can even make the item choices change every month, so to get a certain item, a player would have to wait a year to be able to get it again if they don't get it then. You don't even have to repeat the items, you can always add new ones and the old ones will only be able to be won in events, like the pinkie pie hair for Valentines. There will be three items in total, with those three items changing every month. In addition to the item selected, a title will be earned by both players.

That must have been confusing, so here, have an image.



Having a list of all the players you referred is optional.

/support

Man, this would get me so much cheese. But, perhaps, let's not give 'em expensives because, come on. You know how the email confirmation gets cheese earring? Maybe something at the same "rarity" as that.