2011 hat Facebook noch behauptet, User außerhalb Facebooks nicht zu tracken (was natürlich schon damals nicht so war). Heute gibt Facebook den Datensammelcharakter seiner Like- und Share-Buttons ganz offen zu.
Millions of Facebook “Like” and “Share” buttons that publishers have added to their pages and mobile apps will start funneling data on people’s Web browsing habits into the company’s ad targeting systems. […] the types of sites you visit could be used to tune ads shown to you inside Facebook’s social networking service, its photo-sharing service Instagram, and mobile apps that use Facebook’s ad network.
Abhilfe: Vollständiges Blockieren der Facebook-Buttons.