You've probably used Pandora, and found new music that way.  But there are sooo many other ways to find music.  Here are a few:

• Muxtape initially allowed you to create all sorts of mixtapes.  But now it seems restricted on which music is included.
• YouTube's Video Discovery project allows you to find music by finding similar videos.
• Google also has a Music Discovery engine.
• And there are search capabilities that cover other sites...