Without those changes, many IT managers would remain reluctant to even consider the iPhone for business use. With those features in place, Apple was able to begin building market share for the iPhone, both at home and at work.

Another key move: The iPhone 3G was launched in 22 countries on one day, marking its worldwide emergence before a much broader audience than the original iPhone. Unfortunately, the weight of all those global iPhone activations had a downside: Apple's servers couldn't handle the sustained load of activations, causing problems for first-day buyers. Even so, millions of iPhones were sold in a single day around the world, making the launch an unprecedented success.

Even as Apple has pushed the iPhone out into more countries, rivals have scrambled to keep up. , and yes, I'm looking at you, BlackBerry Storm.

The iPhone SDK and App Store: Apps, apps, apps

An integral part of the iPhone 2.0 software announcement was the creation of an . Designed by Apple, it empowered anyone who wanted to download the iPhone software development kit (SDK) to try his hand at creating his own iPhone application. This was a major advance for the iPhone that, like its new enterprise features, enabled it to compete with other mobile systems, most of which already supported third-party app development.