On a snowy day like this one, in the early days of YouTube, I watched some video or other. A list of other things I might like to watch next ran down the side of the page. The first few were obvious, but then it got kind of random. “Would you like to see a short film about how they did the plumbing in the fountains at the Palace of Versailles?” Never thought about it before, but yes I would. It turned out to be fascinating. Alas, now they’ve improved the algorithm so much that it always knows dozens of identical videos to suggest. It never has to take a wild guess. It’s been a decade since I’ve been interested in a “recommended” video.