Kristen Purcell, the associate director for research at the Pew Internet & American Life Project, notes that one in 10 of 1,917 adults surveyed this spring by her institute wasn't sure if his phone came loaded with apps. Of the ones who did have apps on their phone (or at least knew they did), about one-third said they didn't use them.

"Yes, there is this incredible apps market growing right now, but it is a little bit ahead of the average consumer. The average cellphone user isn't there yet," Ms. Purcell says.

She bets they will catch up, and so do manufacturers of mobile devices. Microsoft (always late to the party) just launched the Windows 7 Phone: an operating system it hopes will take away a share of the mobile app market, currently dominated by Apple. Also nipping at Apple's core is Research in Motion, makers of BlackBerry, who plan to launch the BlackBerry PlayBook (a challenge to the iPad) next year.

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