Those are pre-mixed edits and mashups that artists use for their own shows. Trying to live-mix a lot of songs quickly can become a nightmare when you consider a horde of 10000 fans screaming at you for all the mistakes you made and the money they spent on the show.

This is actually one of the reasons behind the 'press play' argument that went on in the past couple of years. However, consider the fact that the professionally produced and mastered mashups/edits sound much better than a on-the-fly attempt, and you can see where the line between producer/DJ blurs considerably. Readying a mashup specially for a show is taking adequate preparation five steps further by making sure things sound great and the party continues.

When u use CDJ with traktor scratch.no delay ar?? cause i try to setup with CDJ 800mk2.kinda delay when u want play cue etc2.