The format that was supposed to be dead is filling overnight hours in six major markets, and programmers say the numbers are not close.

Late-night slow jam blocks are cheap to run, easy to sponsor, and hold listeners far longer per session than daytime rotations. One programmer described average quarter-hour figures he had not seen since the late nineties.

The bigger question is what it feeds. Independent artists report that a single overnight spin can move a song onto editorial playlists within days.