"Quite a bit" is very relative. I think there are a bunch of individuals who have developed apps and sold it for some decent $. But on a larger scale, there ar

"Quite a bit" is very relative. I think there are a bunch of individuals who have developed apps and sold it for some decent $. But on a larger scale, there are few venture-backed cos without formal API agreements who have not run into trouble. Those are really the ones I was addressing. Like you said, ones who succeed have an exit plan in which case they are not really relying exclusively on the APIs so it becomes a moot point. A guy building an app on top of an API and the app taking off is still building "cute things" in my book. And yes, every now and then you can make a quick buck from the cute thing.