Jared Benson, writing on Idlemode, has given us the 10 essential attributes of mobile presence:
1. Presence should not be interruptive. Imagine how irritating it would be if your pocket vibrated every time one of your mobile buddies' status changed.
2. Users must set/maintain their own presence information. Or, more accurately, users have to have control.
3. Setting presence should be quick, simple, and easy. Amen. Make it hard, and it won't get used.
4. Presence should accommodate for a contact’s different phones. Communication is person to person, after all, not device to device. All presence systems need to observe this principle.
5. Presence should allow users to display different statuses to different groups. Preach it brother!
6. Mobile presence should include communication preference. Agreed, but it needs to be even simpler than the syntax that Jared proposes.
7. Presence should include a universal visual/icon system for quick reference. Jared proposed green / red, and another colour for blocked / not available. Yup. At iotum we also use Yellow for busy, but interruptable.
8. Presence should allow connections to other mobile services. Location based services, landlines, etc. Absolutely. Remember the principle — communications is person to person, not device to device.
9. Presence information should be seen anywhere a contact is referenced in the mobile UI. We live in a Web 2.0 / Web services world. Why stop at the mobile? Integrate it everywhere — the mobile UI, the web, the desktop UI.
10. Presence should be maintained by a non-carrier third party. Spot on. Carrier to carrier federation models will be difficult to manage. A third party is a much better solution.