Good job Mozilla! Do what Google never will - put users' privacy front and center.
On a sidenote, I might now re-enable cache that I kept disabled (well - cleared on exit) because of supercookies. I don't care that much if a single page tracks me, but I _really_ don't want Google to track me across sites. If Firefox protected me against that.. they would have one very grateful user. :)
EDIT: this also highlights why Google is so invested in Chrome - they can make sure that privacy doesn't interfere with their money-making machine. They really are brilliant. Brilliantly evil.