Auctions can make sellers different amounts of money depending on the type used. Different auction types are studied to see which one makes the most money for the seller. The type of auction that works best depends on the bidders and the item being sold. This is important to consider when designing auctions, especially online. The characteristics of the item being sold can affect which auction type is best. The study also looks at how auctions can be inefficient on the internet and gives examples of this.