Facebook's collection system is through share buttons. Those share buttons do cookie share because the domain is Facebook, but the technology is certainly there

Facebook's collection system is through share buttons. Those share buttons do cookie share because the domain is Facebook, but the technology is certainly there to track by ip address and device fingerprint, even if you are not a fb user, and a single fb login redropps the cookies and allows association of your internet media behavior with your FB account and behavior.