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:
The “thin portfolio” concept (borrowing from the prior “personal information aggregation and distribution service” concept) represents the idea that you don’t need that portfolio information in one server; but that it is very helpful to have one place where one can access all “your” information, and set permissions for others to view it. This concept is only beginning to be implemented.
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TubeMogul is a free service that provides a single point for deploying uploads to the top video sharing sites, and analytics on who, what, and how videos are being viewed.