[gregn610]

That https://panopticlick.eff.org link was interesting, but I don't see what about my user agent string makes it so unique (1: 76540.09) ?

  Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.62 Safari/537.36

Looks fairly generic, I think I'm running a mainstream chrome browser on a mainstream OS.

[Matt3o12_]

One problem is that your user agent is matched against all tested user agents from all times. This includes very old ones. If the user agent was used to track you online, they would account for that it frequently updates and for a lot of users (considering that most browsers update automatically these days).

So the site should really only take into account your OS, maybe its major version, and browser version (which changes frequently so trackers can’t rely on that). Or at least not count any that are not used anymore.

[Tepix]

Using Javascript the page can query more details about the environment including installed plugins, addons, configuration settings (language etc), certificates and fonts. That combination is often unique.

[RobertRoberts]

This is amazing, I use Ghostery, Privacy Badger and Scriptsafe in Firefox, and I was MORE private in non-private window! wth?

I suspect it's partly because these plugins don't function fully in a private window?