Elon Musk, the chief executive of Tesla Motor, speaks at the South by Southwest Interactive festival in Austin, Texas, March 9, 2013. Music has been integral to the mobile experience since the early days of iTunes, which upended the old models with its 99-cent per song buying approach. Now, as smartphones and tablets supplant PCs and virtual storage replaces songs on devices, mobile players from handset makers to social networks realize they must stake out a place or risk ceding control of one of the largest components of mobile device usage. Photo taken March 9, 2013. To match Analysis MUSIC-STREAMING/ REUTERS/Gerry Shih (UNITED STATES – Tags: ENTERTAINMENT SCIENCE TECHNOLOGY BUSINESS TRANSPORT) – RTR3FC10