Yes, and there are lots of ways they can do it. Web pages are a flexible platform for exchanging information, but that also means it can be easy to track what you're looking at on them. The first method is through third-party content. Say Company A is an advertising or tracking firm. When you visit sites that display A's ads or use A to track their visitors, A can identify your browser and see what pages you visit on those sites (and more). To learn how to mitigate these tactics, go to ssd.eff.org/cookies. Also, if you click on links to A's site from other sites, A's site can tell which page you came from. To circumvent this, copy and paste the URL instead.