YouTube turns 20: From ‘Lazy Sunday’ to ‘Hot Ones’

The grainy footage, uploaded on April 23, 2005, of a man standing in front of the elephant enclosure at the San Diego Zoo — “All right, so here we are in front of the elephants” — does not look like the sort of thing that would touch off a video revolution.

And yet, two decades after that inauspicious start, YouTube is now a cornerstone of the media ecosystem. It’s where people go for music videos and four-hour-long…