Fueled by the expansion of smartphones and the availability of unlimited data packages, the U.S. mobile internet market grew 74% between Feb 07 and Feb 09 according to Nielsen. The most talked about handset, the iPhone, had a U.S. audience of 5.1 million unique users in January 2009. Though this still represents just a fraction of the mobile universe, the device has had an undeniable halo effect on mobile media adoption.