The object of a good chorus is to produce something that is memorable. That's why so many Spirituals and Gospel songs make such good chorus songs - they were written in an age where not only did few people read and write, but were deliberately kept illiterate. The only way of passing information around was to memorise and say/sing it. It's also why so many shanties and work songs have repetative choruses for doing during repetative tasks. The rhythmn of the song would determine the rhythmn of work.

Not everyone can sing, but I defy anyone to not be able to stamp/clap/shout out a rhythmn (except for captive TV audiences - for some reason they can never clap in time).

A standard chorus would have a strong beat, a memorable or repeated lyric and a tune that is easily learned.

LTS