Problem with the selling domain names is this: You are "most of the time" dealing with a clueless average Joe who has no knowledge of escrow, transfer, nominet etc. I used efty.com but quit because when you agree on a sale you are alone with the potential buyer and need to explain them all before-mentioned stuff. The basic rule should be if you care about the magnitude of the sale price. If I am dealing with a GBP500 guy I don't care about him. He can wait he can cancel or get lost. However if I am dealing with a GBP5000 possible sale I use my words wisely and ready to pay 9 percent commission happily if I am guarded by undeveloped.com.