Online bidding sites are websites that allow users to place bids on items for sale. The most popular online bidding site is eBay, which is a four-letter word. eBay was founded in 1995 and has become the world's largest online marketplace, allowing people to buy and sell goods and services. It allows users to bid on items in an auction-style format, with the highest bidder winning the item. eBay also offers a variety of other services, such as payment processing, shipping, and customer service.