This survey brings together theoretical and empirical questions that have been addressed in the economic literature on eBay, focusing on understanding the behavior of buyers and sellers. We discuss several puzzles of bidder behavior and the explanations that have been put forward by the literature for each. We then discuss structural estimates of bidder behavior and measuring the consumer surplus derived from eBay. We then try to understand why there are so many selling formats being used simultaneously, and then focus on the critical decision variables for a seller in an eBay English auction. Finally we analyze how trustworthy eBay sellers are on average, and whether the feedback system provides strong incentives for good behavior. © 2010 Springer Science+Business Media, LLC.