This category presents the options relative to users properties and permissions.
Profile defines which fields of the profile will be modifiable by the user. By default, the e-mail cannot be modified by the user himself.
Personal agenda lets you decide whether a user can register personal events in his calendar.
Allow users to change e-mail without password allows users to change their e-mails without having to provide their password. This is particularly dangerous as the e-mail address is where the password reminder is sent, so if someone steals another user's connection, he can change the password and prevent access by the legitimate user. The default option is to not allow it without having to give one's password, which is more secure but a little more complicated.