Handy link: https://addons.mozilla.org/en-US/firefox/addon/multi-account...
(+endorsement: it's a really great feature for power users)
(+endorsement: it's a really great feature for power users)
I'm not going to get my mother to use containers to keep her banking separate from her knitted craft forums, the same way I'm not going to get her to use a password manager, but I can install the Facebook Container and buy her a book to write passwords in so she uses more than two different ones.
The new 2.x release of Facebook Container allows people to use "Log in with Facebook". To do so, it adds the site into the Facebook Container so sub-resources and 3rd-party cookies are available to the Facebook SDK js.
It warns the user before they enable this on any site.