*Identity* | Your identity is shown by a screenname, which remains persistent through time. There are incentives not to change this, like having your list of friends stored on the server and only accessible through your screenname. This acts as a pressure to not change identity. Having a persistent identity is more important than having one brought in from the physical world. *Presence* | Presence is awareness of sharing the same space, and this is implemented as seeing when your friends are online, or busy. AIM isn't particularly good at group presence and visibility of communication, although other chat systems (such as IRC and early Talkers) use the concept of "rooms" and whispers. [...]