How much would you pay for a game you could get for one cent?

Last week, indie developer 2D Boy announced that to celebrate the one-year anniversary of their award-winning game, World of Goo, they would let customers set their own price for the downloadable version on Windows, Mac and Linux, usually valued at $20. 

Cynics predicted that most people would pay the minimum PayPal allowed, one cent -- but it turns out many people were willing to pay more even when they didn't have to (and even when the game was readily available on torrent sites). Survey data they collected indicated that most people paid what they were able to afford, not necessarily what they perceived the value of the game to be. 

What could this mean for free-to-play or microtransaction-based models of gaming? Does it speak to customers' support of indie developers in particular? What are people willing to pay (monetary or otherwise) for a good gaming experience? How important is quality (art and aesthetics) versus length? 

We have a similar game to World of Goo on our site -- BridgeCraft -- but of course, instead of paying to play the game, advertisers pay for real estate in and around the game (although we suppose you 'pay' by allowing advertisers to inundate your mind with subliminal messaging...).

This brings up the question of whether BridgeCraft would work as a downloadable title. What if you were allowed to choose your own price to play the game instead of watching advertisements? How much would the game be worth? Are you willing to pay more than you technically have to? 

As online gaming grows both on casual gaming portals such as Candystand and on networks such as Facebook, MySpace and Bebo (all of which support popular social games) -- types of games that people have not traditionally paid out-of-pocket for, what types of content will they be willing to pay for?