Application: Presence
Goal: maintaining awareness of people, devices
- Changes in state occur on O(minutes)
- Sample Event: “Elvis has left the building…”
Monitor “buddies” or “editors” (1-K)
- Infrastructure typically designed for N-N, though
Notifications can be lightweight (text)
Names: users-from-directories, groups
Transformations: batch update; state timeout
Privacy requires knowing who’s watching