You can change your userdata via the register card "personal settings".

Stud.IP speichert so wenige Daten wie möglich.
For "open" systemes (where you can do the registration on your own) you only need your full name and your email adress.
For "closed" systems these information come from a central directory service.
All your further information are voluntary.
You can change further data via"Navigation" . On the following help pages you will find all the information for that.
In general all the date will only be used within Stud.IP and are only visible to registered users.
There may be exceptions for lecturers or assistants e.g. their office hours can be visible beyond Stud.IP.
When you dont want that someone can see your personal profile of Stud.IP you can make it unvisible. How you can do that you can read here.

For illustration you can watch the following video: (:flowplayer width=750 height=432 src=Dark videoFile= autoPlay=false loop=false :)