40 million US mobile subscribers (15.6 percent) actively use the mobile Internet, making the US a leader in mobile Internet adoption, according to a report released today by The Nielsen Company. In 16 countries tracked, the US leads in penetration, followed by the UK (12.9 percent) and Italy (11.9 percent). Among other findings, Nielsen Mobile identified the top 10 US mobile websites as of May 2008.

Nielsen Mobile, a service of The Nielsen Company, published the paper which examines the global mobile Internet market. Among other key takeaways of the report:

• The US mobile Internet market, with 40 million active users, has reached a critical mass for mobile Internet marketing
• The Motorola RAZR phones are the most popular phones among US mobile Internet users, while Nokia handsets lead the market in Europe and Asia
• Unlimited data packages are increasingly popular with mobile Internet users. Today 14 percent of US subscribers access the mobile Internet with an unlimited data package, and 50 percent of data users say that they prefer the unlimited pricing model.
• 3G networks drive user satisfaction with mobile Internet, and these networks improve data throughput speeds as much as six times, compared with 2 and 2.5G networks
• Advertising is becoming a common part of the mobile Internet experience. Today 26 percent of mobile Internet users view ads while using the mobile Internet.
• Mobile Internet users are more receptive to mobile advertising than average data users

“With highly capable devices, improving network speeds and millions of mobile users visiting individual websites over their phones, we believe mobile Internet reached a critical mass for mobile marketing this year,” said Nic Covey, director of insights at Nielsen Mobile and author of the report. “A confluence of factors will only further ignite this market, rapidly, this year and into 2009.”

The paper, “Critical Mass: The Worldwide State of the Mobile Web,” draws on Nielsen’s broad portfolio of mobile consumer and market research to provide insights on the universe, devices, data plans, network speeds, websites frequented and the mobile Internet marketing opportunity in the US and internationally.