Eight weeks ago, Facebook took their boldest step yet: they went live with the Facebook Platform, giving unprecedented access to developers. On May 24 Facebook chief Mark Zuckerberg declared to techies worldwide, "We want you to be able to build a business and make money with your applications. That's all your revenue."

This would usher in a whole new, vastly more functional Facebook. To developers it was a modern-age gold rush. With the promise of immediate access to all...