Socially translucent systems.
Systems that provides perceptually based social cues which afford awareness and accountability.
They developed "Babble", a messaging systems where conversations are persistent, synchronous and a asynchronous. In the systems the users are represented on a circle as marbles: the closer to the center the more engaged in conversation.
In a pane there is a list of conversations, in another pane the list of users, in another the representations of users as marbles, and in the last the conversation itself, made of messages of users represented sequentially in the same text.
The conversation was more free than in email, there was group awerness. Someone created it's own "space", a kind of blog.