Hello there, at the risk of sounding like a newb, I have to ask what is mentioning? I just got an alert telling me that some one "mentioned me" on a thread. I'm not all that sure what that may mean.
It means someone pinged you C:
To ping someone: @ USERNAMEHERE no space!
It's called pinging. :) You put a @ in front of someone's username if you want to notify them that you're talking to them on the forums.