What is EDM?

For everyone who is unfamiliar with the term and its culture, or just beginning to discover it, here is a bit of background information on Electronic Dance Music. 

Electronic dance music (EDM) is electronic music produced primarily born from nightclubs and other environments with dance-based entertainment. The term emerged in America in the late 1990s and describes a set of percussive music genres that largely stem from the production methods of disco music, techno music, house music, and trance music. It uses lively synthetic beats and bass lines with sometimes vocals involved. 
It was first marketed to the United States as "electronica" music when it first got its popular exposure in the 1990s, but did not have a large impact yet at the time. In 2011, Spin magazine reported that the American dance music scene had finally reached critical mass with a "new rave generation" of mainstream consumers having emerged. Today it has become common for established Top 40 artists and producers to infuse elements of popular EDM styles in their music. In 2012, for the first time, the Grammy Awards even included EDM in their categories.

Some world-wide popular EDM artists (click to visit their site): 

Afrojack

Avicii

Skrillex
Deadmau5
Swedish House Mafia

Swedish House Mafia's latest single Don't You Worry Child. The music video encompasses what an EDM concert looks like (on a large scale)