Bundling Customers: How to Exploit Trust Among Customers to Maximize   Seller Profit
  We consider an auction of identical digital goods to customers whose valuations are drawn independently from known distributions. Myerson's classic result identifies the truthful mechanism that maximizes the seller's expected profit.   Under the assumption that in small groups customers can learn each others' valuations, we show how Myerson's result can be improved to yield a higher payoff to the seller using a mechanism that offers groups of customers to buy bundles of items. 
Elchanan Mossel and Omer Tamuz
cs.GT