Really like the idea. At first, I thought you were building a funnel for your other venture, but this application has much bigger vision. My one primary turn-off here is relevance of the reward to what I'm signing up for. I'm sure this is what you're going after and hasn't materialized yet due to lack of offers to pass around. But I'm curious how you're planning on solving this in a way that scales well.

PS: Tidy up those "Reward Detail" popups! Keep it up!

PPS: The email link on the about page is "protected" (hi [at] rewardlevel [dot] com) whereas the email link at the top is not.