I've been doing stuff with the Facebook Graph API for the past week and I must say it's been the most frustrated development experience I've ever had. The documentation is so poorly written and out of date that it's virtually impossible to understand anything of it. Facebook development seems like a combination of black art and a bag of tricks. Not to mention that if you develop for Facebook integration there is no way to decently test your application. My guess is that this will severely impact the developer base for Facebook apps which will result in less and less companies willing to advertise on the platform.