In what is widely regarded as his greatest presentation ever, Apple's Steve Jobs introduced the iPhone to the world on January 9th, 2007. In the five-plus years since then, the iPhone, iPad, and iPod Touch have literally redefined the entire world of mobile computing. That world is moving so quickly that iOS is already amongst the older mobile operating systems in active development today. That certainly doesn't mean it's underpowered or underfeatured — quite the contrary. Through what can only be described as relentless and consistent improvement over the years, Apple has made iOS one of the most feature-rich and well-supported platforms on the market.