I used to work at the Old Town School of Folk Music, the nation's largest community arts school. After the film Cold Mountain came out in 2003, we had great turnouts for our shape-note singing workshops. As a church musician working a second job at a not-so-churchy place, I took no small pleasure in hearing the old Sacred Harp hymns at work.
Several of the Sacred Harp melodies have survived in modern hymnals, but they've largely been domesticated by more standard part-writing. The original harmonizations are wild and droning and wonderful—and not heard in churches much anymore. This interesting news piece by Greg Garrison finds shape-note singing in a perfectly symbolic setting: an old church building in Birmingham that's now part of a university campus.
It's terrific that there's been so much interest in recent years in various forms of sacred American traditional music. I just wish that more of that interest was coming from churches.