You can engage some of the people in real time some of the time. You can engage desktop-computer users when they're at their desks. Sometimes you can engage notebook users at Starbucks. But only when users go mobile can you engage all of the people in real time all of the time. That's why mobile devices are the fastest-growing and most fascinating field in real-time market engagement.
As the rapid proliferation of browser-equipped devices like Blackberry and iPhone puts millions more Americans online all-the-time each year, the United States is catching up with mobile-centric markets like India and Africa. It's true: Mobile Internet connections are more widely used in the rest of the world simply because phones are what people can afford and wireless infrastructure is more reliable than landlines. Even in Japan, a land with last-mile optical fiber that puts the United States to shame, mobile rules because online prime time is the two or more hours people spend riding trains each day.
From here I'll lump together everything from simple handsets to iPhones under the catchall term "mobiles." The really critical distinction is between mobiles with and without GPS (Global Positioning System).
Adding GPS capability to a mobile transforms a general window on the online world into a lens focused on its proximate surroundings. With GPS, a mobile gains awareness of nearby people, objects, and offerings that trumpet their location online. So ...