I suppose some kind of list of users signed up for the programme could be a possibility, that has their referral link, plus their total amount of referrals and name of the offer. For instance,

User X, (iPod mini), 2/5
User Y, (XBOX 360), 1/8
User Z, (XBOX 360), 5/8


If the list grows too large, it will definitely be almost impossible for EVERYONE on the list to get all their referrals from other Zelaron members. But that doesn't prevent anyone from getting a few signups on their behalf here and there. Hmm, I'm just ranting.

Anyone sign up for the XBOX 360 yet?

"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram