The U.S. market for ad-funded mobile entertainment will grow to $336 million by 2013, expanding the overall mobile media market by 4.6%, according to a new forecast. The study by the Mobile Entertainment Forum, a global trade organization, predicts that brand-subsidized content will account for the majority of revenue at almost $263 million, while the balance will come from upselling premium content. Mobile video and TV are expected to represent 41.4% of ad-funded revenues within five years, followed by music at 34.5% and gaming at 24.1%.--Mark Walsh