Tweener Devices Fall Between the Cracks of Usefulness
I've noted before that there's a limit to the number of digital devices end users will carry (it's three) , and for that reason, users have embraced the overlap of features that marks today's devices. As the quality of photos and the quantity of music that a cell phone can deliver increases, users have been more likely to leave their dedicated digital cameras and music players at home.
But the cell phone doesn't completely rule the mobile experience. The laptop still does a lot of things that a cell phone can't master. Now we're seeing the introduction of "tweener" devices meant to bridge the gap. Mostly, they aim to do things that can be done on a laptop and at best rather poorly on a cell phone. But they certainly won't eliminate the need to carry more than one device, and it's doubtful that they will replace many laptops.
In the long term, the phone is going to be difficult to displace. Part of the reason the cell phone is ubiquitous is that it is pocketable. Being highly accessible because it doesn't have to be lugged around in a carrying case, the phone is a primary device. And the core of the cell phone is voice communication, the feature most valued by consumers. For all the functionality that vendors have added to phones in recent years, the core value of voice communication (followed increasingly by other means of communication) will keep the phone at the top of the consumer device hierarchy.
At the other end of the mobile spectrum and increasing in mainstream adoption is the laptop. While the phone is ideal as a communication device and suitable for looking up information, the dimensions that make it ubiquitous also make it unwieldy for use as a content-creation device. Not many business trips are made without a laptop in tow. And the laptop has also evolved. PCs are no longer only used for content creation; they have also become a medium for storing large collections of content and a portal for personal entertainment. A business productivity tool that is also an entertainment device is going to be tough to displace, and that doesn't even take into consideration the PC's tight integration into business and educational infrastructures.
Over the years, many devices have attempted to bridge the gap between the phone and the PC. Small but not pocketable, they have offered limited productivity tools. Consumers have consistently rejected them. Today, a whole new class of underpowered netbooks and other mobile Internet devices fall into this same in-between category. While today's tweener devices offer connectivity in addition to their other features, these devices are neither small enough to be pocketable nor powerful enough to meet increasing consumer demand for functionality. While the contextual nature of mobile computing will determine which devices get carried and when, it will be difficult for vendors to displace either the phone or the laptop with devices that fall squarely between these two categories.
Mobile devices are following two contradictory trajectories. One class is fragmenting in terms of core functions, creating new markets for stand-alone devices such as dedicated cameras and media players. The other, which includes such devices as smartphones and mobile Internet devices, is taking on new features and functions, rivaling stand-alone devices in terms of functionality through convergence. Neither approach is universally correct, and vendors more than ever need to understand the contextual factors that influence consumer device usage. They have to focus on providing the sorts of core features that will lead users to include these devices among the three that they're willing to carry.
Devices that can't displace one of those three will simply not be purchased.