"There is a big controversy happening right now, about this election particularly, regarding Facebook. There is this claim – which hasn't really been proved, substantiated, but it's getting pretty popular – that Facebook rigged the election because they showed fake news," Snowden said.

"If that was true, if that was possible, and Facebook just put on fake news, and we were persuaded [by it], I think that's actually very sad indictment of our democracy that our voters could be so easily misled," he added.

However, fake news isn't the biggest problem on the table, Snowden thinks: if it's true, then "this gets into a bigger challenge, which is the lack of competition."

Indeed, come to think of it, can we imagine a Facebook replacement?

"There seems to be no alternative to the larger services. Because of this network effect, because the first mover advantage. When you get a Google or a Facebook or Twitter in place, they never seem to leave," Snowden said.