If outrage is the business model of social media, then US President Donald Trump has just handed the shareholders of Twitter and Facebook another gift.

This week's threat from the tweeter-in-chief, to clamp down on alleged bias in social media, is certainly ominous. But, based on drafts of Mr Trump's proposed action, the chances of any serious change to how the platforms operate are low, while the anger it has stirred up on both sides is already paying off in terms of soaring online engagement.