Eine kleine Option in den Safari-Einstellungen, die wahrscheinlich nicht wirklich viel bewirkt. Aber vielleicht sollte man es einfach anmachen, damit die Firmen merken was die User wollen und was nicht. Twitter zum Beispiel hält sich an diese Einstellungen.

Do Not Track is a technology and policy proposal that enables users to opt out of tracking by websites they do not visit, including analytics services, advertising networks, and social platforms. At present few of these third parties offer a reliable tracking opt out, and tools for blocking them are neither user-friendly nor comprehensive. Much like the popular Do Not Call registry, Do Not Track provides users with a single, simple, persistent choice to opt out of third-party web tracking.
http://donottrack.us