Earlier this year a video of Nancy Pelosi, the most powerful woman in US politics, was posted on Facebook. It appeared to show her slurring. There was a suggestion she was drunk. It was proved to be a hoax, but Facebook refused to take it down.

Now a video showing Facebook founder, Mark Zuckerberg, saying he’s taking control of people’s lives, has been widely shared. This hoax has also stayed online.

So can we believe anything we see online?