Ballmer didn't anticipate how the form factor of the iPhone and having the internet in your hand would fundamentally offer different ways to communicate beyond

Ballmer didn't anticipate how the form factor of the iPhone and having the internet in your hand would fundamentally offer different ways to communicate beyond just email. He overlooked how capable the device would be for text messaging, social media, video calls and that the new device would shape how we communicate going forward. And not to mention the myriad of apps and other use cases the iPhone would have.