Someone just referenced my account in his question. I believe this is might not be a feature even supported by StackOverflow. But it would be cool to know who reference you in his questions.
Example:
[insert name] proposed something cool in a different question while [insert name2] proposed something different. Can anyone tell me whatever about these 2 solutions?
So I had in mind that it could take that form, when someone creates a link to your profile in a question or in an answer. You get notified about it since you might not be watching the current question. In that case, the referenced person may or may not respond but was at least notified that someone used him as an "example"...
And it could also take the form of badges. If you are referenced 50 times or something like that.
edit
Since some people are actually getting scared about spamming. Notifications don't have to be immediate. For example, the example below shows some kind of abuse. Abuse as far as I know isn't tolerated on SO. In other words, the question would probably get edited or closed before it even try to send a notification to the linked users.