For system administrators and IT professionals. People who manage and maintain computers in professional capacity.
For computer enthusiasts and power users. Questions about computer hard- and software.
Superuser is still in private beta now, but I'm sure a real "superuser" will find a way to get the key to access the site.
- Meta Stackoverflow.com
Questions about Stackoverflow, Serverfault and Superuser.
The next enhancement will be to create one gadget which supports all of the sites such that just one of them has to be added and you can dynamically turn on/off each of them separately.