Well, in theory it sounds good. If you could make it so it would only send one email and not keep sending emails till they log on agian that would be nice. Or maybe a seperate screen in the USER CP that would have a list of threads the user was mentioned in.
A couple of things to think of..
1) Make sure that it does not include the "QUOTE" part of the message.
2) Try to limit the amount of emails the user could get. If it was a moderator on a board or a very active member, they could be involved in a ton of posts and get their name mentioned.
I had more, but I can't think of it right, now..
Josh