If you want to prevent tracking, on Firefox,Ghostery and uBlock Origin are your friends
That and a nice hosts file will keep you out of a lot of trouble
This new Firefox feature sounds really sweet, this makes a lot of sense. If all the Operating Systems can support "multiple users", why can't our browsers, in 2016, support segregation of web sessions?
Make the frontier the Window, the browser instance, the tab, I don't care. Just give us the option to have multiple identities when connected and that's a huge step forward.
The "incognito" or "private" mode was a step in the right direction, but that makes the total number of simultaneous identities to 2: the incognito window and the normal one.
I believe this is a good step on the right direction, decoupling the sessions from all the "infrastructure" (cookies