Thinking also of "where are they now?", today I chanced across this picture, which looks like a very ordinary businessman or politician. I was quite startled to realise who it was. The URL gives a small clue.

That is a bit of a surprise. I had to Google for the picture to find out who it was, though!

[Raak, Darren] Was just reading his "dangerous idea" at Edge. Profound knowledge of the philosophical implications of quantum mechanics or windy hallucinogenic rhetoric?

[Projoy] The dangerous idea was asking him the question in the first place.

Well, who is it then?