Availabot is a tangible presence awareness device designed by Schulze and Webb:

Availabot is a physical representation of presence in Instant Messenger applications. Availabot plugs into your computer by USB, stands to attention when your chat buddy comes online, and falls down when they go away. It’s a presence-aware, peripheral-vision USB toy… and because the puppets are made in small numbers on a rapid-prototyping machine, it can look just like you.

Look at the Matt-Jones implementation :)

It's yet another tangible representation that can be used in IM (see the Nabaztag also, thie wifi rabbit that can move its ear if you get a Gtalk message), here the specificities are:

Because Availabot works entirely over USB, you can plug in as many puppets as you have USB ports (or friends on your IM buddylist). (...) Availabot stores the IM details of the friend it represents in the puppet itself. (...) Each Availabot is customised

Why do I blog this? it's a good step towards tangible artifacts connected to Net; I like the customization issue (very important in a DIY culture) and the fact that you can plug multiple Availabots. What is also pertinent is that they are producing prototypes to investigate what works, before thinking about sth larger.