Prior to the App Store's arrival, the iPhone may have been groundbreaking in terms of its design and user interface, but it was nowhere near as capable as it would later become. Unleashing the creativity of third-party developers was arguably the key to unlocking the iPhone's full potential.

While Steve Jobs was reportedly initially against third-party apps on the iPhone, Apple quickly came around the idea, and by early 2009, the company had fully embraced the app economy as an integral part of the iPhone experience. "There's an app for that" even became the slogan of a famous iPhone commercial.

Over the past 15 years, apps have fundamentally changed the way we communicate, play games, date, listen to music and do countless other things, all while creating a huge opportunity for independent developers around the world.