Mark Gimein has a great article on Swoopo.com
Jonah Lehrer ponders why this website is attractive:
I think the real appeal of the website is the sheer uncertainty. As an item nears the end of bidding, a big countdown clock appears. At any moment, someone else can come up in and bid on the item, which then resets the clock to twenty seconds. The process repeats and repeats, until the price gets to a point that discourages other bidders. (It's probably less discouraging to you, since you've already sunk $50 in bidding fees.) But here's the dirty secret of the site: after placing a bid, you're forced to wait and watch. You have no way of knowing if your bid will win, or if someone else will swoop in and bid on the laptop at the last possible second. In other words, it's just like a slot machine: you put in a quarter and wait for the wheels to whirr. With swoopo, the random number generator is other people.