Stars Launch Jay Z's Music Streaming Service

Rapper Jay Z has officially launched his new music streaming service, named Tidal, with the help of some of the biggest names in entertainment. Madonna, Rihanna, Beyonce, Kanye West and Alicia Keys are among the A-list celebrities who co-own Jay Z's new venture. Speaking at the launch event in New York, Alicia Keys said Tidal aims to "forever change the course of music history". Tidal is likely to face tough competition from existing streaming services like Spotify.