After claiming 27% of US smartphone market share in the last quarter of 2007, the iPhone has slipped to 20% for the first quarter of 2008. Where have all the iPhone buyers gone? Apparently to RIM and Palm (why!) who saw their market share increase in the same period. For Palm, the gains can be credited to the rise in popularity of the Centro and for RIM, well no one doubts their powerhouse status around these parts.

There could be plenty of reasons why iPhone market share has slipped. For one, the shortages could be a big part of the puzzle here, people aren't buying iPhones because there aren't any iPhones to buy. Another reason could possibly be educated consumers who realize that the iPhone 3G is imminent thus delaying their purchase. Not to kick the iPhone when it's down, but the price and carrier-locked nature of the iPhone could also play a role in its diminished market share.

Regardless, the iPhone is still driving smartphone interest and increasing the market's sales and its competitors are posting lower market share than a year ago. My personal take? I want to see device-by-device sales numbers. The iPhone is a one man army against multiple fronts from RIM and Palm yet still manages to be more than competitive. Narrow down the numbers and specifying the models could paint an entirely different picture.

Or maybe not. iPhone 3G to the rescue? What do you think?