The white and gold W910i Walkman handset comes preloaded with content from Def Jam artists including Mariah Carey, Ne-Yo and Ludacris. As Reuters Technology Correspondent Matt Cowan reports, the Def Jam branded phone is just the latest example of how the music industry is looking to the mobile sector for new sources of revenue and artist promotion. As Reuters Technology Correspondent Matt Cowan reports, the Def Jam branded phone is just the latest example of how the music industry is looking to the mobile sector for new sources of revenue and artist promotion.