The advent of the MP3 format made music more portable. Add the technology to support it, you have a legion of earphone/headphone addicts roaming everywhere. Back to the days of cassette tapes, Sonys' Walkman seems to be the in-thing. Then came the mini-CD players then Steve Jobs. Everybody else knows what MP3 is. Everywhere you see people sporting their own portable MP3/music players.
The MP3 player revolution introduced us to the whole new concept of playlists. Yes, with the advent of the technology , people were given the freedom to build their own playlist and not just restricted pre-arranged songs that came along with cassette tapes and CD's. Now you can choose your own favorite songs from different artist and albums and play it over and over again without the discomfort of bringing dozens of junk CD's or tapes.
After playlist, came an even more enticing feature, shuffles. This is the lazy way of generating a random playlist from your music collection. Just dump all your music into the player, shuffle it all or do some filtering based on the genre or artist name. That's easy non stop music for you.