A lot of people have been complaining that the iPod touch is missing some of the features of the iPhone. It’s true; whilst similar in some details – touch screen, music player, web browser – the touch is also missing several features present on its more expensive cousin. Email client; editable calendar; etc.

But perhaps lacking is the wrong word. No doubt part of this is to do with keeping cost and size down, but I think it’s also intentional on Apple’s part, regardless of the price of components: the iPhone is a productivity device; the touch is an entertainment device. The features absent from the touch are exactly those features that make the iPhone a productivity device: phone, email, full calendar functionality. By creating a clear destinction between the two devices, Apple can avoid undercutting the more expensive iPhone by presenting customers with a choice between two different kinds of device, rather than two devices of the same kind that differ only in that one can make phone calls.

Apple wants to give customers compelling reasons to buy an iPhone. Having only one mobile productivity device on sale, rather than two, is certainly compelling. If you want to send emails, make appointments, and yes, make phone calls, buy an iPhone. You’ll be able to listen to music, too. If you just want to listen to music, watch YouTube, maybe visit your favourite websites, but don’t care about sending emails on the go or editing your calendar, buy a touch.

Of course, this isn’t to say that the touch is purely for entertainment, or that the iPhone is purely for productivity. You can check your business webmail on the touch, or watch YouTube on your iPhone. But the primary focus of each device is different, and by creating this distinction Apple have done a lot to protect their iPhone sales. The touch could have been an ‘iPhone without the phone’: same feature set, only phone functionality missing. But this would have been a far more compelling alternative to the iPhone, and an alternative to the iPhone is exactly what Apple do not want – not even from their own product line.