I came across this article on how to monitor your webmail account:

http://www.snpx.com/cgi-bin/news55.c...19695850?-2622

Basically you get hold of a free webcounter and set it up in a fake e-mail. The idea is that if someone opens the mail this will set off the webcounter and record their details.

I am afraid that that sounds rather like closing the stable door after the horse has bolted to me but it might have its uses depending on circumstances?