Three sided-cloud

There are three sides to the cloud:

1. The authoring tool. I edit and update a feed. It contains a <cloud> element that says how a subscriber requests notification of updates.

2. The cloud. It is notified of an update by the authoring tool, and then in turn notifies all subscribers.

3. An aggregator. Subscribes to feeds that may or may not be part of a cloud.

What they call real-time 

via http://dashes.com/anil/2009/07/the-pushbutton-web-realtime-becomes-real.html via http://dashes.com/anil/2009/08/what-works-the-web-way-vs-the-wave-way.html