>I asked this question because at this time I am using extreme tracker on my site.
Hmmm you think maybe spam is having some adverse affect on us making us a bit hostile these days? *g*
Now that I understand your question I can tell you that Extreme Tracker is not collecting the EMail addresses but rather letting you know when someone has linked to your site via an EMail message they received.
Imagine if you sent a friend an EMail saying "Hey check out my site, the url is...." if they click on that link directly from their EMail program then Extreme (and most other stat systems) can identify the EMail program it came from....
It will look something like this:
(I stole this from another tracker) Showing that someone checked their mail using Yahoo Mail and clicked a link to get this particular site.... (for those who wondering NO this does NOT give out the mail boxes password..)
Hope this helps