Still, concerns about Facebook's role in shaping political attitudes are unlikely to abate anytime soon.

Some people object even to voter-registration drives. Wikileaks founder Julian Assange, for example, alleged this week that Google and Facebook were trying to encourage a "remain" vote in Britain's referendum on European Union membership by encouraging voting, asserting that media users are disproportionately youthful and pro-Europe.

A more common complaint is that Facebook and other social networks serve as an echo chamber of ideas and beliefs, as users decide which people and pages they will follow and customize their News Feed.

A 2015 study in Science showed that Facebook users tended to interact and click on content that was more in line with their ideological views.

Facebook customer Tom Steinberg wrote in a post this week -one that quickly spread over Twitter - that he had actively looked on Facebook for people celebrating Britain’s vote to exit the European Union last week but could not find any.