This is pretty cool: Firefox has a new extension that isolates your Facebook session from the rest of your browsing. That way Facebook isn’t able to track you as you visit every website that happens to have a Like button or embedded FB comments.
Facebook still knows what you do *on* FB, but this cuts down on their ability to track you elsewhere.
Facebook Container Extension: Take control of how you’re being tracked – The Firefox Frontier
The Facebook container extension helps you control more of your web activity from Facebook by isolating your identity into a separate container. This makes it harder for Facebook to track your activity on other websites via third-party cookies.