Wich Function to Autolink Usernames

Hi,
if i wrote a Username with an @ then the Name will be a Link to the Userprofile.
Whats the Name of the Function?

Example
Mrd
[MENTION=11609]MrD[/MENTION]

This is a mod from .org that we installed. it doesn't really work correctly.

Hi Brain,
thx for the Info.
I Use a bb Code to do that, but the automatically Link is a fine Thing if it´s work correctly