The bonus varies from year to year--cash, Disney bucks, merchandise or whatever. It's usually worth a couple of hundred dollars and kicks in only for purchases directly through DVC itself. There are two ways to trigger it. Either notify your guide BEFORE your friends place their first call and ask for that guide, or tell your friends to mention your referral during their FIRST conversation with any guide--at which point they'll be transferred to your guide. If the first conversation passes without any mention of the referral, the bonus disappears.