Another factor cutting into PDA sales is users' growing reliance on laptops for basic functions they used to reserve for PDAs. Other developers continue to experiment with wearable and highly portable computers. A company called Handkey has developed a device called the Twiddler, which is a keyboard and mouse that can be held in one hand.
Also, the Context Computing Group at Georgia Tech is testing speech-recognition devices that would essentially make PDAs speech aware.
Convergence, wireless networking, usability testing and increased CPU power are helping to redefine the way we think about mobile computing. Many -- myself included -- still find value in the simple PDA that serves as a calendar, address book and to-do list. However, our next device may well be magnitudes more powerful.
Sources: eMarketer, MIT Tech Review