Rihanna, Beyoncé, Nicki Minaj signing the Tidal For All contract 2015This afternoon, Jay Z formally launched his new streaming music service TIDAL with an all-star event in New York City. As it turns out, Jay Z is merely a co-owner: Arcade Fires Win Butler andRgine Chassagne, Kanye West, Jack White, Daft Punk, Beyonc, Chris Martin of Coldplay, Rihanna,Madonna alsohave ownership interests in TIDAL.All these artists were at...