Ask HN: Is there a tool for selectively giving targeted referral bonuses?

I was wondering whether there is a mechanism to give referral bonus (e.g. "refer a friend and you both get $10 if they sign up") to only users with a high probability of bringing quality leads (or vary the referral bonus by the potential quality of the lead). For example, a naive version of this would be "if it's using a Facebook or Twitter identity, target this to users with X number of friends/followers". Thanks in advance!