[wvenable]

The iPod was an MP3-player killer. And the iPhone was a smartphone killer. In neither of those situations did Apple create the market -- they improved what other players were doing. Outside of Android, there were no new smartphone designs to tout as iPhone killers. My WinMo phone's underlying design predates the original iPhone by a long time even though the device itself is newer. Microsoft is finally getting around to making their iPhone killer with Windows Mobile 7.

[nmcfarl]

Actually I think the first 2 sentences here nail this for me.

If your aim is to own a category, and you have a chance at designing an awesome product.

If your aim is to dethrone the current market leader in a category - well your odds are a lot lower as your focus is off.