Slam poetry is a form of performance poetry that occurs within a competitive poetry event, called a "slam", at which poets perform their own poems (or, in rare cases, those of others) that are "judged" on a numeric scale by randomly picked members of the audience.
In a Poetry Slam, judges, randomly chosen from the audience, score poets on a scale from one to ten - the poet with the highest score at the end of the evening wins. The audience participation and the democratic nature of the event (often signing up is all that is required to perform at a local venue) have helped the Slam catch on across the country.
"But is it really poetry?"
That question has been asked ever since Chicago poet Marc Smith started Slam Poetry in 1986.
Related: Saul Williams