Jon Udell wrote a brief piece on how data is locked on servers behind UIs that were not designed for data sharing. He views this as "data friction"...it's just the perfect way to describe the problem.
I couldn't agree more with Jon's take. I would even take it further: an operation-centric approach to interfaces is good for closed systems or systems where semantics are completely centered around behavior; however, the data behind those operations is still somewhat locked-in. Data-centric APIs that expose a uniform interface for clients to consume is how the class of scenarios that Jon talks about will come to life. We can't tell upfront how all those applications out there will use our data, it's just too hard to predict, so a "function centric" interface just won't do. Instead, those systems need put out the data plus a way to interact with it that enforces proper semantics while not getting in the way of how a consumer wants to explore that data.
We're hoping to help at least a bit in that space with Project Astoria...we'll see how it goes 🙂