Tracking the Evolution of Cookie-based Tracking on Facebook.

We analyze in depth and longitudinally how Facebook's cookie-based tracking behavior and its communication about tracking have evolved from 2015 to 2022. More stringent (enforcement of) regulation appears to have been effective at causing a reduction in identifier cookies for non-users and a more prominent cookie banner. However, several technical measures to reduce Facebook's tracking potential are not implemented, communication through the cookie banner and cookie policies remains incomplete and may be deceptive, and opt-out mechanisms seem to have no effect.