Decades before the Internet, radio stations reached out to listeners via weekly playlist surveys. The sheets were usually handed out in record stores and contained the week's top hits -- and usually pics of the station's top DJs.
I'm old enough even to remember radio station surveys, as they were still passing them out as late as the 1980s. But obviously the web made it easy not only to publish playlists, but let you interact with your favorite radio station in ways unimaginable back then.
Here in Los Angeles, top 40 once ruled on 93/KHJ ("Boss Radio"), KFWB/98 and KRLA. Some surveys from the 60s: