After two weeks of experimenting with a variable pay scheme and collecting data, 2D Boy had posted about the results on their site. All the stats are gathered from the 83,250 copies sold through donations. This article is a follow-up to the one posted on October 19th, and there are over six thousand of replies that you can read in their survey results as well (for the thoughts and comments question).

Related:
World of Goo's Big Sale (Spiderweb Software)