That's a cool feature but it requires the poster to remember to use the @ symbol. My suggestion is something more automatic. Now that I think about it a bit more, it's probably not do-able given you would have to have a way to quickly search every word against a table of users.
I think it could be great to know when and if I was mentioned in a thread.
For instance:
User xyz posts: "I just spoke with msantarc and he suggested that you try..."
Now the next time I log in, I 'll see a note saying: " msantarc you have been mentioned in the following (1) posts: (link to...