How much music can you put on websites?
You can put as much music on a website as you'd like so long as the hosting server is physically able to hold your desired amount, so long as you follow the legal procedures to store music on your websites (in short, do not resell or share it under loose or nonexistent conditions).
You can get music vids off youtube and share them. A music sharing website is a website that you can listen to music. Most of the music sharing websites are free, and some are you have to pay. There are a lot of good music sharing websites out there. Some good ones would be (pandora.com, playlist.com, las.fm., and there are so many more. but those are free music sharing websites.)