Several months ago Prosper introduced a referral program. Under that program Prosper members can receive $25 dollars for referring a lender, and up to $125 for referring a borrower. I referred my brother and my wife, both of whom became lenders and funded loans on Prosper.
Much to my surprise today in the mail I received a thank-you card from Prosper thanking me for referring a friend. Along with the card there was a free t-shirt. Looks like this might be one of Prosper's new marketing campaigns.