Check out Ghostery, a Safari extension (also available for Firefox, Chrome, and Internet Explorer). With Ghostery installed, whenever you visit a Web page that uses such tricks to track, you’ll briefly see a box listing all the services that are tracking your visit to that page.
I’ve been using Ghostery for a while and really like the way it reminds me of just how much tracking is going on and it shows you just how ridiculous the situation has gotten. One page I visited had 54 trackers on it. Needless to say, it was a painfully slow web site.