When Mr Jack Dorsey made the sudden public announcement that he had quit as CEO of Twitter, it was only ever going to have happened in one place - Twitter itself. It reminded me very much of Mr Elon Musk's entertaining tweet adventures, as Mr Dorsey tossed his resignation letter onto the social media platform that he co-founded. You could imagine him sitting back to soak up the theatre of reaction and speculation that unfolded.

This isn't Mr Dorsey's first resignation letter to Twitter - he was forced out of the CEO chair in 2008 only to return as executive chairman three years later - and no one can say for sure if it will be the last.