On this evening in 1920 a small station in the Detroit News building, call sign 8MK, went on the air with what it would later call the start of regular daily broadcasting — music and talk for the few dozen people in Detroit who owned a receiver, most of them home-built, and who happened to be listening. Eleven days later it read the Michigan primary results into the microphone. (Pittsburgh’s KDKA, which got the famous “first” in November, would like a word; that argument has run for 106 years and I am not about to settle it tonight.) 8MK became WWJ and is still on the air.

Here’s the clever bit: the audience was a few dozen sets, and the sets were built by hobbyists. You do not wait for the audience. You go on the air, and the audience builds the sets.