After only 15 months of use, my trusty Treo 650 is headed for retirement. I can no longer live with the erratic throughput, timeouts and other productivity-robbing artifacts I have had to endure. I'm also convinced that the Palm OS is doomed, despite the arrival of the Treo 700p. The plan is to go with Windows Mobile, which supports both the Slingbox and the VPN I use for remote access. I'm no fan of Microsoft, but the handwriting is on the wall: Windows Mobile is going to be at the top of the mobile OS heap, whether we like it or not.

But my main concern isn't the operating environment; it's the keyboard. I was discussing input metaphors for mobile devices with a few colleagues recently, and one thing on which we agreed is that no single method works for everyone.

I'm mostly a fan of microkeyboards. The two-thumb technique, popularized by the RIM BlackBerry and now dominant on PDAs and smart phones, is usually quite fast and accurate with just a little practice.

The telephone keypad approach, while still prevalent, appears to appeal only to teenagers. I find it quite frustrating when I'm in a hurry (and when am I not?), even with the various clever assists developed over the years (such as T9, which links the letters found on each phone key with a fast-access dictionary of words).

Go for the micro
Then there's the pen. This can work pretty well for selecting items, and I've met people who got really good with Graffiti (which seems to have disappeared regardless), but I think those people are few and far between. Taking notes with a device that tries to recognize my scrawling is an exercise in frustration for both me and my electronic pal.

So, microkeyboard it is, although I've never gotten used to the keyboard on the Treo 650; the keys are just too close together, and too many characters require multiple nonobvious key presses.

Our discussion of input got quite heated when the subject turned to voice. Voice would be ideal, one might argue, because we have thousands of years of experience with it; further, though there are hundreds of natural languages used by the technically literate, at least the physical layer is consistent across them.

Now wouldn't it be great to be able to interact with applications using only your voice? Wouldn't it be great to be able to dictate, rather than type? Well, yes it would.

Except that we're still some ways from speech recognition that's sufficiently accurate, and speech really isn't a good idea in every case. I've yet to use any speech recognition tools that work really well. The limited processing power of the mobile device and the highly variable acoustic environment further compromise voice input.

Then there's security. If you want to gather competitive intelligence, just listen to people on their cell phones. They must speak loudly, of course, because in the quest to save a few milliamps they don't get any feedback in their ear and thus shouting becomes the norm. Perhaps general education on the performance of condenser mics would be of value. Anyway, voice isn't going to be the input metaphor of choice for most.

I'm intrigued by alternatives that make the keypad really useful for text entry, such as MessagEase (a keyboard approach from Exideas) and the Thumbscript technology.

The problem with the Treo 650 is that it's too narrow for the keyboard. If we really could use the keypad for quick, accurate text entry, there could be a dramatic effect on form factor--and on the variety of mobile devices actually useful for Web and e-mail access.