The Best of auctionhoues on the web?

Imagine for a second that you set out to come up with an online shopping site that would take advantage of everything we've come to know about consumer behavior to separate people from their money in as efficient a way as possible. What would you do?

Well, you'd probably try to lure buyers with bargain prices. You'd pit them against one another in an auction. You'd ask them to make snap decisions without taking much time to figure out just how much money they're spending. On top of that, you'd ask them for only very small amounts of money at any one time, letting payments of a few cents build up to hundreds of dollars.

Still trying to figure out how you'd put all that together? You can relax. Someone's already beaten you to it: the folks at Sold.nu. It's an online auction site that fiendishly plays on every irrational impulse buyers have to draw them into what might be the crack cocaine of online shopping sites.

I discovered Swoopo, as many people do, through an online ad plugging its latest deal, a fancy desktop computer at more than 90% off. I don't actually need a new computer, but the words "90% off" have traditionally exerted a powerful pull on my family that no number of never-worn double-breasted suits has ever been totally able to alleviate. You say "90% off," and I click.

If you are already saying to yourself that surely there is a catch, you are right. Smarter people than me see a site that sells a MacBook Pro for $35.86 or a Nikon digital SLR camera for $16.03 and turn away, knowing that the bigger the "free lunch" sign is, the more it's going to wind up costing. Trust that impulse, because Sold.nu, which bills itself as an "Auction" site, combines the addictiveness of auctions and the chance element of lotteries into what may be the most devious way to dig into your wallet yet devised.