Marketplaces and auction sites offer a central portal where multiple vendors can sell items from a single site. Amazon for example carries merchandise that is fulfilled by individual sellers. For the consumer this simplifies the shopping experience. They can visit one marketplace to purchase from multiple vendors and compare prices, reviews etc.
Auction sites are similar but typically offer a dutch auction presentation (where you bid on an item and the high bidder wins) as well as fixed price “buy it now” items.
Channergy supports multiple marketplaces and auction sites so you can maintain all your inventory and customers in a single database.