Esp tailored clients. Mirror how you are doing business. Going back and forth between flat and hierarchical. Context Directory contains contexts. Contexts contain participants.
Agents can behave like people.
Example is an agent that takes notes in a meeting, an automated participant. Agents must be traced back to some person that is responsible. You can t hold roles responsible. NetMeeting provides sharing for arbitrary application and number of people. It is a simpler commercial CSCW tool.