Schoology is a startup that seeks to address many of the pain points of the LMS: Schoology is easy to use. It's free. It offers data portability. It encourages communication and collaboration with look and feel of contemporary social networking sites rather than the bulletin boards of circa 1996. But it isn't simply a social networking tool. Schoology provides the functionality of its big name competitors - Blackboard, Moodle.
In Activity Streams, verbs are their own objects, and the variety of actions that can be represented is limited only by the standard itself. Providers can also use verbs outside the standard, taking the chance that they'll eventually be incorporated, or that a downstream client could parse them anyway. Here's a list of the verbs incorporated in the Activity Streams standard so far: