The tracking of users' online activities once they have visited a Facebook site even after they are logged off from Facebook's main site. The Facebook tracking uses software cookies deposited on the user's computer which are activated any time a user visits a site displaying a Facebook "Like" button or other social plug-in. The cookies tell Facebook the date, time and Web address of the site, as well as the network location or IP address, browser and the user's computer operating system.

Facebook tracking has become a controversial topic due to privacy concerns.