If you don't want websites tracking you, and you don't want the pages you view to be saved in browse or search history, you need to active the incognito mode and this is what you need to do.
Let me show you how to achieve that Depth Of Field effect known from the photography using Gimp. With other words, how to make selected area of the photo sharp and the rest out of focus.
If you have activated the option to store passwords in Mozilla Firefox, than you can easily look at all password you have entered when you were browsing websites.