Groupon actually has substantially changed their payout terms, from their 10-Q http://investor.groupon.com/financials.cfm

> Our current merchant partner arrangements are structured as either a redemption payment model or a fixed payment model defined as follows:

> Redemption payment model - Under our redemption merchant partner payment model, we collect payments at the time our customers purchase Groupons and make payments to most of our merchant partners at a subsequent date. We utilize this model in most of our international operations as it conforms with the local market practice. Using this payment model, merchant partners are not paid until the customer redeems the Groupon that has been purchased. If a customer does not redeem the Groupon under this payment model, we retain all of the gross billings for the Groupon purchase. The redemption model generally improves our overall cash flow because we do not pay our merchant partners until the customer redeems the Groupon.

> Fixed payment model - Under our fixed merchant partner payment model, we pay our merchant partners in installments over a period of generally sixty days