The iPhone was a well-reviewed hit from the start, but its sales momentum took a while to build. Now, each mid-year refresh kicks off a sales spike: The iPhone 4 sold more devices in the first three days it was available than the original iPhone sold in its first three months.
Even without the traditional June refresh this year, iPhone sales still hit a record high in the spring.
Here's how Steve Jobs made Apple the most valuable technology company in the world.
