It would be usefull if all principal classes (not only users) had a functionality of storing attributes.
In the application I'm working on groups are corresponding to some organizations (e.g. companies) and their attributes (name, address, etc.) must be strored in a separate table. Besides an obvious inconvenience, there are also difficulties in regular removing Jetspeeda groups as their records are referenced by my tables. Probably some other functions of principal attributes could be mentioned.