Tim Bray speaking about the Virtual Data Center API specification goals:
This is a unified view of the storage and compute and networking services. It’s built around the notion of a “Virtual Data Center” (VDC), which contains networks and clusters of servers and public IP addresses and storage services. The idea is to give you the administrative and operational handles to build something really big and ambitious. The VDC notion is really slick and I think something like it is going to be required in any serious cloud API going forward.
Tim Bray is giving also a high level rationale for the RESTful API:
Why, then? Simply because we wanted a bits-on-the-wire interface. APIs, in the general case, suck; and are really hard to make portable. Bits-on-the-wire are ultimately flexible and interoperable. If you’re going to do bits-on-the-wire, Why not use HTTP? And if you’re going to use HTTP, use it right. That’s all.
Update InfoQ has published a couple of days ago an interview with Tim Bray on the Future of the Web (nb IMO a must see).