Not only is YouTube a great place to learn new things it is increasingly becoming a place where creative types can show off their stuff, subverting traditonal channels of production and traditonal formats.
It's really inspiring to watch the ways in which people are able to use new technologies to create new formats. Web television is particularly exciting, covering a variety of genres from cooking and talk shows to sci-fi and musicals it's all there somewhere. Shows like 'Dr. Horrible's Sing Along Blog' and 'The Guild' are good examples of this. Many web shows encourage viewers to comment and contribute, creating a more interactive enviroment than traditional television. They even have their own awards night for web shows, The Streamys.
In particular at the moment I am more than a little addicted to a web series called 'The Lizzie Bennet Diaries' which is an awesome, beautifully adapted, modern take on Jane Austen's 'Pride and Prejudice'.