I recently noticed something weird. From time to time I watch on YouTube (Firefox) something political. In my case 'lastweektonight'(left) and 'StevenCrowder'(right), (because it is fun to see, where each party lies). Anyway I noticed, when I watch a video from StevenCroder the next video in line, is always a video from lastweektonight. I think, I made myself look like an undecided voter...

Then it occurred to me, how can they do that, if I do not have an account? I deleted my YouTube browser history, nothing else, and checked again. I clicked on a video from stevencroder and the next video in line was one from stevencroder. How can they read my browser history?

  • Does the same thing happen if you run your browser in private (or incognito) mode?
    – mti2935
    Feb 26, 2020 at 18:37
  • @mti2935 --- I'll check, but i need some time building up my history again.
    – Myxir
    Feb 26, 2020 at 19:02
  • 1
    Websites don't read your browser history. They usually have trackers that will fingerprint your browser. Clearing your browser history doesn't affect websites or tracking. Clearing cookies will affect some tracking (and log you out of some sites), but it doesn't do much about your browser fingerprint. Feb 26, 2020 at 19:28
  • @Fire Quacker --- That is what I thought as well. I know about Canvas & Cookies that are used to track people. However, once I deleted my browser history, the behavior of YouTube clearly changed and it is freaking me out.
    – Myxir
    Feb 26, 2020 at 19:39
  • @Myxir that's because you deleted your cookies
    – schroeder
    Feb 26, 2020 at 19:47

1 Answer 1


YouTube uses cookies which helps them track you and suggest videos even if you do not have an account.

But using the "Forget this site" from the History tab, you removed those cookies:

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions [emphasis mine]


So, no, YouTube did not have access to all your history, just your history on YouTube since they stored a cookie. Firefox has always had all your history because it is your browser, but YouTube does not have access to it.

  • they probably use cross site cookies from google ad networks as well. Feb 26, 2020 at 20:49

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