Customers buy bids in advance (costing $0.75 each in the US, or 50 pence in the UK). Most "auctions" begin at $0.15 or 8 pence, and increase by the same amount with each "bid". Some items, known as "penny auctions", only increase by $0.01 for each bid, but still cost contestants $0.75 per bid. Each bid also increases the auction's end time by 10–20 seconds. Although the contest winners often pay a low price, Swoopo earns money from the bids placed.
Seems legit. The buttons work and link to other pages on the site...The first (but not conclusive) way to determine if a site is bogus if the buttons don't work.