it is a sad fact of conducting business online that frequently once you have sold to somebody, they may never come back. It’s not quite as much a consequence of your business or your product as much as it is a bizarre facet of patron psychology — unless we are completely stunned with a product, we’re very improbable to buy more than one copy of it. This holds particularly true for online marketers, where the target is just about always to sell only one product to as many folks as feasible.