It does depend what you mean by the overloaded "web services" term. If you just mean in the sense of a generic API (restful or otherwise), then for c) I'd incl

It does depend what you mean by the overloaded "web services" term. If you just mean in the sense of a generic API (restful or otherwise), then for c) I'd include defensio, and then I use all the API from bug.gd and featurelist.org (because we use them a lot internally) I think widgets and the like will be using these a lot more often. Right now, we tend to develop everything of ours as web API first and then grow them into widgets, apps, Flash, ajax on top of that as needed. Saturation is a harder question-- I can't say that I'm sad at all that more companies/initiatives are opening-up APIs.