It appears Web Intents has taken the time-tested concept of an enterprise service bus (http://en.wikipedia.org/wiki/Enterprise_service_bus) and used it in a non-enterprise application - namely social networking / bookmarking.

Here's a few ways that makes this promising:

- Using a common set of standard services makes communication application-agnostic

- It reduces dependencies across applications - applications can change, but the services remain the same

- Innovation will be driven by features, not by adoption of one application's API vs. another application's API - this plays into Google's philosophy that innovation should ultimately prevail

Interesting stuff.