Completely "log out" of FB, to protect your WWW privacy:
If you do not delete those cookies, WWW pages with a "Like" button will continue to tell FB that YOU visited THAT page.
Yes, it is that bad. But in 3 minutes you are free.
Then perhaps share this pic? Thx.
(high quality version of the pic: http://i.imgur.com/3YA0rvL.png )