Wow, has anyone here ever set multiple cookies? People are blowing this up bigtime. Facebook sets multiple cookies, one for an active user session and another token that serves to authenticate a user has previously logged into facebook, so they don't need to enter extra security questions.

Who else does this? Major banks, forum software, etc. It's a common technique. All that matters is what Facebook actually does with the data, and their privacy policy, just like the Engineer stated.

If you're paranoid, either don't use Facebook or clear your cookies after you log out. Don't you just love simple solutions?