According to a new report from The Nielsen Company, twenty-three percent (58 million) of all U.S. mobile subscribers say they've been exposed to advertising on their phones in the past 30 days.  Half (51% or 28 million) of all data users who recall seeing mobile advertising in the previous 30 days say they responded to a mobile ad.The bi-annual Mobile Advertising Report from Nielsen Mobile, of more than 22,000 active mobile data users, reveals that:

• The number of data users who recalled seeing mobile advertising between the second and fourth quarters of 2007 increased 38% (from 42 to 58 million subscribers)
• Teen data users (ages 13-17) were the most likely age segment to recall seeing mobile advertising (46% recalled seeing some type of mobile advertisement, compared to 29% of all data users)
• Asian-Americans and African-Americans are more likely to recall mobile advertising (42% and 40%, respectively) than all data users
• 26% of those who saw an ad responded at least once by sending an SMS text-message, the most popular ad response.  9% say they've used click-to-call to respond to a mobile ad
• 32% of data users said they are open to mobile advertising if it lowers their overall bill
• 13% (18% of males) said they are open to mobile advertising if it improves the media and content currently available
• 14% said they are already open to mobile advertising so long as it is relevant to their interests
• 23% expect to see more mobile advertising in the future (up from just 15% in Q1 2007)

While just 10% of data users said they think advertising on their mobile devices is acceptable, an increasing number of mobile users appear to understand the value proposition of ad-supported mobile content, says the report

The report concludes that advertising researchers must examine the ways in which audiences are and are not willing to engage with mobile advertising, as media companies and marketers explore the unique ways they can interact with consumers supporting mobile media content through advertising revenues.

For more information on the study, please visit Nielsen here.