What Makes the iPhone Work
Gruber, on why the iPhone is so successful:
One obvious but wrong answer would have been for Apple to start with a phone. That's what most companies in the mobile handset industry have done and it's led them to a dead end. The problem is that while successful complex systems evolve from simple systems that work, not every simple system that works can support additional complexity. It's not enough just to start simple, you have to start simple with a framework designed for future evolution and growth.
Consider that none of the major new features in the iPhone OS 3.0 software is related to the telephone. MMS comes closest, but even that doesn't pertain to phone calls. The "phone" in "iPhone" is much more about ubiquitous always-on wireless TCP/IP networking than it is about the 20th century conception of telephony.
And that's the main reason I'd like an iPhone. Always-on internet access, anytime, (almost) anywhere -- and it fits in my pocket.