[timClicks]

Whenever you build a service in someone else's garden, there's always the (fairly high) chance that you'll be booted out at some stage.

In a sense, platform APIs allow the platform owner to understand what customers want without needing to deploy product talent to deploy it. Twitter has perfected this strategy. As soon as a third party comes up with a neat idea with your API, you can build your own "official" version of their app, throttle their usage and hopefully their business model.