User management

Hello everybody,
I am looking for a CMS – user management – that will allow me to to add users and allow them the possibility of created an extensive user profile . Basically, I am looking for a user management script – or CMS – with heavy customization options.
Basically, what I want to do is something like a social network, but very private. It will be used at a local school.
If you know something that can help me achieve this, I would greatly appreciate it.
Thank you!

See original post by MarSteph