Every time a user edits his/her profile, it checks the name, username and e-mail. If any of this information differ, it sends an e-mail to all administrators with system notifications switched on.
The notification contains the changes and the previous state.
It is a great tool for admins that want to have up-to-date information about their users.
A few more options would be nice, ie choosing the email address(es) to send to, choosing the text for the email but the important info is already in there.