Where is social media going to draw the line?

It’s far from clear whether Mark Zuckerberg can fully eradicate the worst material lurking in Facebook’s darkest corners, even if he wants to

Mark Zuckerberg made an extended appearance at Georgetown University in Washington DC recently. He had a message to impart about Facebook and its editorial challenges. To an attentive audience, he talked about free speech and how the social media giant was dealing with the challenges posed when the public have open access to the digital airwaves.

He came in for criticism, not surprisingly. Some said there was little new in the talk. My ...