‘Blue days, all of them gone’, Al Jolson sang, almost a hundred years ago. ‘Nothing but blue skies from now on!’ Mr Jolson’s sunny sentiments seem to have been oddly prescient. For 97 years later, the great and the good of the public sphere – well, at least the ones who never stop telling themselves and us how great and good they are – are decamping en masse from X (formerly Twitter) to rival social-media site Bluesky.
