"The iPhone has shifted power in the US smartphone market away from carriers and mobile software companies, and toward hardware companies like Apple," said Michael Mace, a principal at Rubicon Consulting, as Rubicon today released a new survey showing that the iPhone is providing big benefits to both its users and the companies that sell it. "The challenge for Apple is moving iPhone demand beyond early adopters and current Apple customers," Mace added.

To continue its momentum, Apple needs a strategy to attract people beyond its installed base, and fix problems like the compatibility limits in the iPhone browser, Mace contends. 

"Mainstream users may not be as entranced by the iPhone's many features as are early adopters," he noted. 

The report shows that US iPhone users are very satisfied with the product, and that they're making heavy use of features like e-mail and browsing. This is driving higher mobile phone bills, producing about $2 billion a year in additional revenue for AT&T, the exclusive mobile carrier for the iPhone in the US.

But the survey also showed that most iPhone users are young early adopters, about 75% of whom are previous Apple customers. And they're not universally satisfied with everything about the device -- about 40% report that it can't display all the websites they want to visit, and many also said they would like to see physical changes to the product, such as the addition of a bigger screen or a thumb keyboard.

The Rubicon Consulting iPhone User Survey contacted 460 randomly-selected iPhone users in the US in March 2008, and queried them about a broad range of issues, including satisfaction, usage patterns, and expenses. The survey has a margin of error of about plus or minus 3.8 points at the 90% confidence level.

A full report on the survey findings is at www.rubiconconsulting.com, and the report can be downloaded at http://tinyurl.com/2rkyve.

• AJAXWorld Report: Inaugural iPhone Developer Summit in New York City
• Windows Mobile Discussion During iPhone Developer Summit