That's part of the problem. Even in web services, a 90% profit margin is unrealistic. So if you're doing the same volume as Google (operating margin of around 3

That's part of the problem. Even in web services, a 90% profit margin is unrealistic. So if you're doing the same volume as Google (operating margin of around 30%) but making only 5% RPU, you're probably not profiting much. That's a lot of why Facebook is only barely profitable, whereas Google was making a killing when it had their traffic levels.