If this intrusion into your privacy bothers you, The Wire has published a simple solution that only takes a few minutes. And it doesn't cost anything. All you have to do is click here. That will take you to a website that automatically scans your browser to see what companies have loaded tracking cookies on it (so you'll have to do this with each browser if you use more than one).
When it's done scanning (it takes a couple of minutes) you can click the big button you will see near the bottom of the page, and it will clear all of those tracking cookies from your browser. Or you can choose cookies to remove individually if you prefer.
When you're done, you will see a link to an add-on (in Firefox) or an app (in Chrome) you can add to your browser to prevent these tracking cookies from being loaded into your browser in the future.