The news appetite of American’s mobile consumers is “voracious” according to a new Pew Study. One third of American mobile users access news on their phones, and 55% access news information from at least four different platforms per day.

Pew’s new report “Understanding the Participatory News Consumer” is based on a recent telephone survey of 2,259 adults ages 18 and older. As new Internet and mobile tools transform the way Americans find news, those in the business of reporting news are testing out new ways to turn a profit and keep the news flowing. On the front lines of this experimentation is mobile advertising and mobile marketing.

With mobile readers and the soon-t0-be-released Apple iPad gaining popularity as well, paid subscription models paired with mobile advertising are becoming a necessity for the news industry to survive. The Associated Press last week said that it plans to start charging consumers for its content with an app for Apple’s iPad. AP CEO Tom Curley last week disclosed plans for a paid subscription to the Financial Times last week. The Wall Street Journal already charges for digital news and the New York Times will start charging in 2011. Subscription models for print still need to be supplemented with advertising revenues, and in mobile news the need for advertising dollars to support the content business is no exception.

Another notable finding of the Pew report is that people use multiple platforms to access their news. The report states that “The notion that people have a primary news source, one place where they go for most of their news, in other words, is increasingly obsolete.” Meanwhile, news is now less about the actual news, and more about the social commentary on news. Pew says that 37 percent of Internet users are commenting, Tweeting, Facebooking and otherwise integrating news sharing into their daily lives.