So far mine has blocked 765 sites. WooHoo!
GloryB, tracking you helps business's by putting things you like in front of your nose in hopes you will buy from them.
I use Firefox and I have also installed GoogleSharing.
When I go to a site if you look in the lower left hand corner while the page is loading you can see who is loading stuff for that page.
Almost all of the time Google is right there loading it's trackers. Along with FB.
So I got GoogleSharing
[url=http://www.googlesharing.net/]GoogleSharing :: A Special Kind Of Proxy[/url]
With GoogleSharing enabled, a site that has "Google" trackers will not even load.
For instance, I have to disable it when I come to City-Data because Citi-Data uses Google Trackers. And if it's enabled on a site that uses Google trackers, that site won't load.
Read about what all Google knows about you on the link above.
I don't really think there's a way to stop the tracking altogether but this sure does slow them down.