As you browse the web, the browser you use (Firefox, Safari, Chrome, etc.) stores the pages you visit, for a limited period of time. This can be helpful if you need to return to a site you did not bookmark, but it can also be a pain if you are concerned about buttinskys.
One of the reasons your browse does this is so you can use the back and forward buttons on your browser. In addition to finding sites that I've forgotten, I also find it helpful when I need to open a tab or window I accidentally closed before I was ready.
Unfortunately, this sometimes allows third-party services to access histories, which is for the purposes of seeing where you went and how often (often in relation to advertising,but generally not for judging my incessant need to look up serial killers on Wikipedia, which, busybodys, is because I can't stop watching shows on Investigation Discovery).
Luckily, browsers have settings that you can adjust, and change, so you can browse the web more comfortably. You can also delete your history. Sometimes you can set your browser so it will save zero data.
...We'll look into that soon.