I don't expect to hear Carter Family songs on Top 40 radio, but that is where I heard this song today. It is "Cups", a version of "When I'm Gone", https://www.youtube.com/watch?v=cmSbXsFE3l8
Here is the Carter Family's version: http://www.dailymotion.com/video/xtxjd9_the-carter-family-when-i-m-gone-remastered-country-music-experience_music and a link to a thread on the origins of the song Detail.CFM?messages__Message_ID=2514681 .

Apparently it was included in a movie, "Pitch Perfect", in 2012, and reached number 6 on the Billboard Hot 100 in 2013. The title "Cups" comes from the percussion instruments (cups) used in this version. This was apparently an innovation by LuLu and the Lampshades https://www.youtube.com/watch?v=mhiiuqfxfDg

Perhaps this is old news to you, but it was new to me, so I thought I would share it.

Kent Davis