Over the weekend an interesting API was added to API database: one from 23, a photo sharing service. What's notable is that their API is modeled after the popular Flickr API. They didn't invent yet another incompatible API. Within minutes developers can port their applications from Flickr to 23. A very good, but quite rare, approach in the Web 2.0 API world: API near-compatibility.
More on this topic tomorrow.