Add that to the fact that some people are estimating the facebook app industry to be making over $100 mil, while facebook itself still has trouble trying to moneterize, which is all conducive to facebook (legitimately in my opinion) charging app devs for a smiley face sticker.

But that also opens up an interesting business model for facebook: build the platform for users to use for free, then charge developers to use your platform to get access to the users. They could even go for a flat percentage of the app revenue.