I'm presuming that you're not talking about Firefox's Private Browsing mode, which comes with an actual tracking script blocker. The biggest factor for trackin

I'm presuming that you're not talking about Firefox's Private Browsing mode, which comes with an actual tracking script blocker. The biggest factor for tracking without the ability to store things on the client is IP-based tracking. In many cases, the IP address narrows the number of possible persons down to a handful. Then you can use behavioural analysis, fingerprinting or factor in other data to narrow it down those last few meters. And well, any time you visit a webpage which has a DoubleClick ad on it, uses a font from Google Fonts, incorporates JQuery from Google's server, incorporates Captcha, Maps, YouTube, Custom Search Engine, Google+-Button from Google's server, etc., or in fact, even though this is the least of your worries then, Google Analytics and Google Tag Manager, any time one of these is on a webpage you visit - which is pretty much every time you visit any webpage, your IP address is sent off to Google. And now comes the bad part: As is information about what webpage you're currently on, as part of the HTTP Referrer. And I mean, if your URL is not resolved by 8.8.8.8, you can consider yourself lucky, too. So, Google effectively has your complete browsing history, whether you're in private mode or not. Facebook is not nearly as bad in this respect, but their Like-Buttons are rather widespread, too, and they do have an analytics framework, as you've already pointed out.