YouTube channels are hubs in which an user can upload and present their own YouTube videos. Each user gets their own YouTube channel. YouTube is about to go through a massive update to channels, bringing a more flat, tiled based, layout. Google is calling it One Channel, and  it looks a lot like Metro, in my opinion. If you want to get it, you can enable it for your YouTube channel by following this link: http://www.youtube.com/onechannel