The way it worked on Reddit was that people would post a link to a small audio clip of them singing the song or playing what they remembered of it on an instrument. You could also talk about what happened in the music video, what kind of voices were singing, etc.

If I tell you I can’t remember the name of a tune commonly played at Christmas that has a couple recordings with singing and some just as an instrumental, and on the instrumental there’s a horse whinny and whip crack? You probably know I’m talking about Sleigh Ride.