This is off Wikipedia, I think it answers the original question:
A Linkback is a method for Web authors to obtain notifications when other authors link to one of their documents. This enables authors to keep track of who is linking to, or referring to their articles.
Linkback - Wikipedia, the free encyclopedia
If you scroll down to the bottom of
http://www.airlinepilotforums.com/ma...777-200-a.html it shows all the websites that the page has been linked to, I believe thats what you are getting emails about. (And you may get a new one since I just linked to it
)