Singing a song is three things. There's making a musical sound with the voice. There is drawing other people into singing,if it's a song with a chorus. And there is telling a story or painting a picture. Some people are good at all of them.

If you've got to chose, I'd say the ability to tell the story or paint the picture is the most important. We've all heard people with beautiful voices totally screw up songs, and people with pretty terrible voices out them across brilliantly. And chorus songs are great, but not all the time, relentlessly.

A good song circle provides a setting in which that kind of thing can happen. And I think the best song circles are mostly unaccompanied songs (I mean not accompanied by instruments, I'm not talking about people not joining in on the chorus or refrain)with a song with accompaniment every now and then. And a mixture of all sorts, some loud some quiet, some with choruses and some without.

And if at all possible people taking their cue for what to sing from what's been sung before, so there is a kind of musical discussion going on. I don't mean rigid themes, something much more flexible and drifty than that.