Here is a little info from “Informa Telecoms & Media 2007” which explains the repeated financial investments of venture capitalists in companies which target the entertainment services on mobile.
The market for content and services on cell phones is expected to grow to $150 bln by 2011. SMS, multimedia messaging and instant messaging on cell phones will generate revenues worth $93 bln globally by 2011 from $60 bln 2006 and an expected $67.4 bln in 2007. Entertainment services comprising games, music, TV, adult content and gambling would grow to $38 bln by 2011 from around $18.8 bln in 2006.