Yes, it does track my browsing and tailors ads to that browsing history. What really annoys me it the pop up I get every time I go to Amazon that tells me to install the assistant. I have but I KEEP GETTING the stupid pop up even though I installed the assistant. Now I'm going to uninstall it. I don't get that pop up that I have to DISMISS every time I go to Amazon if I use Explorer or Chrome so maybe I just won't use Firefox anymore. Very annoyed.