The only thing I have ever really wanted to see, I believe is impossible. Greenie and I talked about this some time ago. But, if there was a way to track where traffic was coming from not only from the link on the webmaster's site but the link they took to get there. It would have to involve a browser's history and I would imagine that if it were possible, someone would have done it by now.
Just in case I'm not clear...here is how it would work. A webmaster builds a free site and submits it to 3 link lists. The site gets a few hundred hits one day and on that day, someone buys a membership. It would be great to know which linklist sent the person that bought the membership.
Like I said, it probably isn't possible.
But wouldn't it be nice if it were?