In my last interview with Clay Christensen, who died last month, he said his theory of “disruptive innovation” had provided a “common language” that allowed businesses to frame a problem and decide on a course of action.

It was a typically modest self-assessment. It also provided a clue to the way in which some disruption zealots were able to twist the management thinker’s ideas into a dangerous cult. The theory had had an impact, Christensen said, “largely for good, but sometimes for idiocy”.

Niklas Zennstrom, who co-founded Skype, told me recently how the early assumption that web-based innovations would mostly benefit the world, was “used as a blanket excuse for doing whatever”. The relatively small scale of the network in the 1990s tended to limit the damage caused by any misguided early experiments or morally dubious business models.