XF 1.4 User Tags

I've been searching for this but, so far, no luck.

The user tagging system in posts, what exactly does it do and can it be configured? I know that if you click on a tagged username in a post it will display their profile info box but does it do anything else. Will it, for instance alert the user that they have been tagged in a post. That would be very useful. If it doesn't do that is there a mod in resources that I can install to do it?
Yes, that's what I would have thought, but I tagged a user in a post, and he also tagged me in a post and neither of us got an alert. Do I need to configure something somewhere.