I spent a very frustating evening seeing the Anonymous 4 in concert. They instructed the audience to hold their applause until the intermission. They were (they said)avoiding losing their focus. They did a varied repertoire with several obvious breaks,stopped to change their position on stage and stopped to adjust their pitch. They spent 45 minutes singing to each other and shut the audience completely out of their performance.

I have performed in classical choirs before where we grouped pieces together thematically. The audience got to respond every third song or so.

When I've played in bookstores before I've asked the audience to also express their appreciation to the management and to buy books.