As of 2015, you can play music from a playlist on YouTube by loading a video in the list and pressing play, ensuring you don't stop the playback or switch to a video outside of the list. The music comes from the audio tracks of the videos within the playlist.
The YouTube video service contains a feature that allows its users to compile a series of videos into a single list that automatically plays each video in succession. As the site contains an expansive amount of videos with musical content, typically in the form of music videos, live performances or lyric videos, this feature is commonly used to simulate the playlist feature found on many digital audio devices and services. To listen to music within an existing playlist, play one of the videos within that list and allow it reach the end, so that it can automatically load the next video. It is also possible to jump to the next video in the list by pressing the double arrow button in the lower navigation menu.
To create your own playlist, sign up for a YouTube account. While watching a video, click on the plus sign icon and choose the Create New Playlist option.