This video produced by Sylvain Hunter on YouTube serves as an introductory explanation on what DanceDanceRevolution and related dance games are like in this day and age. It goes over not only DanceDanceRevolution, but what the current StepMania communities are like now and the type of content they typically play.
Check out Sylvain Hunter’s channel here: https://www.youtube.com/channel/UCaq-0QLeMasYuCtF7AJs8IQ