The risk for iPhone users: They know too much

When she whipped out her iPhone, Erica Sadum could feel her husband's eyes roll. But she had a point to prove. And in less than a minute, she was able to report to the skeptics around the dinner table that Menno Simons, whose followers are known as Mennonites, was in fact born in 1496.

Apple Inc.'s iPhone, which went on sale nine months ago, isn't the only so-called smart phone that provides itinerant access to the Web. But its wide screen and top-quality browser make it easy to use and read, which means it can in seconds change a lighthearted conversation into the Pursuit of Truth.

"It's turned me from a really annoying know-it-all into an incredibly annoying know-it-all, with the Internet to back me up," said Sadum, a technology writer in Denver. "It's not a social advantage."

New technology always brings new habits with it, some of them unpopular. The mobile handset took phone calls into the streets and the BlackBerry created a generation of thumb-typing e-mail addicts. Some smart phones hook their owners up to facts and figures that ordinary people pull off the Internet with a proper computer.

As USC student and iPhoner Cliff Smith put it, "I have the ability to clear up any confusion."

Fewer than 1% of the 219 million cellphones in the U.S. are iPhones, according to M:Metrics. (One possible reason: An iPhone costs about $400.) That hasn't been enough to trigger a broader boom of Internet browsing on hand-held gadgets. The percentage of U.S. mobile phone users surfing the Internet over the last year has stayed flat at 13%, M:Metrics found.

Internet companies, though, report that they have been getting more traffic from mobile devices, much of it from outside the U.S. And the companies have noticed that iPhoners use their handsets differently from other owners of mobile phones. They search the Internet more, particularly for movies, restaurants and news, according to market researchers, and they watch more videos on YouTube and do more online banking.

Google Inc., Yahoo Inc. and Microsoft Corp. are betting that mobile services and advertising will be the next big business opportunity. For example, the Yahoo Go service for Internet-connected cellphones (not yet available for the iPhone) showcases a program called PriceCheck. It allows people to check prices at a number of stores by entering a product's bar code number.