A new generation of smart phones and tablet computers is redefining computing. Impressive processing and memory capabilities, sleek touch-screen interfaces, increasingly reliable wireless data networks, sensors such as accelerometers and gyroscopes, and new applications make it possible for people to use these mobile devices in ways that weren’t predicted even a few years ago.

In 2010 consumers bought more than 300 million smart phones—devices that include complete operating systems, and for which advanced software can be written—plus nearly 18 million tablet computers. (Meanwhile, more than 1.1 billion simpler phone handsets with text delivery capacity reached consumers around the world, mainly in poor countries.) “Every person on earth will be carrying a smart phone before long, and that’s going to be making a lot of changes to everybody’s life,” says Monica Lam, a computer scientist at Stanford who specializes in mobile-computing research.

Smart phones such as the BlackBerry and Palm have been around for nearly a decade, but the current surge of interest began with the introduction of Apple’s iPhone, in January 2007. That device—whose total sales hit 100 million earlier this year—started a wave of innovation helped along by a new market in third-party applications that continues to generate novel services and forms of entertainment (see “App Stores Make Billions, but Competition Is Growing”). In January, Apple sold the 10 billionth app to run on its iPhone, iPad, or iPod Touch. But these days Apple’s phones and tablet computers and its proprietary iOS operating system face competition from other devices, many of which use Google’s mostly open-source Android system. Android phones are now selling faster than Apple devices (see “Smart-Phone Operating Systems Control More Consumer Electronics” ). Both Apple and Android devices are increasingly controlling televisions, printers, and other electronics; future versions that include near-field communication chips might be used to control desktop PCs, too.

This mobile ascendance is truly global (see “Broadband Rises, Cellular Rules”). Whether the new mobile devices are stripped-down models in Kampala or full-strength units in San Francisco, they’re providing new ways to socialize, receive news, and transact business.