When you have finished singing, you nominate the next one to sing.

That's an interesting one - can anyone report on how it works in practice?

Someone upthread mentioned the sing-pass-or-nominate system. I've never seen that either, but always been a bit wary of it - I can see it developing into a popularity contest for the votes of the non-singers, which isn't really how I see singarounds! Same question - do people find it works in practice?