Maybe you caught Taylor Swift’s live stream on Yahoo a few weeks back. Yes, that was the 24-year-old music sensation releasing her new album, debuting her new Shake It Off video simultaneously on Vevo and answering Instagram, Twitter and Facebook questions from fans. More importantly, Swift was showing off her mastery of online media as a means of self and music promotion. Social media has changed the music business, which as KWHS explores, is especially powerful for lesser-known artists and performers.…