The camera-phone video, shot vertically, shows a guy in khakis and a blue Google t-shirt. He’s holding a microphone and asking the audience to imagine what it would be like if ordinary people could effortlessly capture stories and share them, from their smartphones.

“What if it was possible to publish them instantly to the web?” he asks the crowd, with a whiff of wonder.

Weirdly, this video was not unearthed in a time capsule buried in the mid-aughts. It was shot last week in Nashville, Tennessee,…