It’s not mobile until you can get a full day’s usage (whatever that means to you, the user,) without ever carrying an AC adapter, spare battery, external battery, etc.

It’s not mobile until it’s the only thing you need to carry in order to use it. If you’re capable of working comfortably on a pure slate, that’s one thing. If it’s a pure slate, and you find yourself lugging a BT keyboard, you’ve just killed most of the mobility.

Finally, it’s not mobile if you ever have to ask yourself, “Do I really need to carry that today?”

This opens up the category by quite a bit. For some people, a 12″ laptop (normal or convertible tablet) is perfect. 4-6 hours of battery life, small enough to fit in most bags, and chock full of input options.

For others, something like the Motion LS800, or a keyboardless UMPC is fine. Smaller, but lacking in certain input options.

For yet others, we head into OQO/HTC Wizard territory. Tiny, wireless, with a decent keyboard. Actual CPU capabilities, of course, diminish rapidly at this point.

As you go down in size, you give up a bit in terms of actual battery life, but that’s what the OQO’s extended battery is for, right?

I’m one for something like the HTC Shift, which adds all the bells and whistles I’d like to my old preferred form factor, the Toshiba Libretto. Sure, it violated some of my own rules, in that I carried a Wifi, Ethernet, and Aircard with me at all times, but connectivity was rarely an issue, and CardBus adapters aren’t that big of a deal. (The OQO is nice, but EV-DO rev.0 bugs me, and the pricetag on such tiny devices just leaps right out of my budget.)

Right now, I get by on a Nokia 770, and it’s far from perfect, but it tends to get the job done, when I remember to charge it.

I teach at a University with (surprise!) extremely proprietary podium pcs. I can’t install any software on them, which means that I have to have everything I need on my person. Therefore, my idea of mobile is a computer that will do everything I expect out of a workhorse of a pc and that I -literally- will not notice in my bag while running around campus. The answer: my Panasonic W5. It is fast, powerful, decent battery life, optical drive, extremely light and even the power adapter is not that heavy. So, for me — mobility means being able to do everything I do at home elsewhere without feeling *any* burden (from slow processing to extra weight).

While I love my p1610, it simply doesn’t compare in the fast-workhorse competition.

Size, battery life, utility, and HEAT.

If it’s too big to carry easily, then it’s not mobile. If it can’t last the day (in your usage pattern; mine does involve long periods on “standby”) then it’s not mobile. If there’s little point in carrying it because it doesn’t serve a need of yours, it’s not mobile. If it gets too hot to hold, it’s not mobile.

That’s a tricky balance.

— Steve

8 hours on the device’s own battery – my ThinkPad x60s is certainly mobile. Use on a bus yes, walking? Sumocat’s Portable might be closer.

Thyere’s no question about my Axim x51v being mobile (IMHO)

If i have to debate with myself about whether to carry a device due to storage or weight issues I don’t think of it as mobile.

Battery life! No matter how small something is, carrying around something that has no juice to run would be dead weight. Also, ideally my ‘mobile’ device would be something that I can use while in transit, whether it be on the bus, or while walking.

I define mobile as being usable without requiring a place to set camp. If I can walk about, stop, do some computing, and then continue walking, it’s mobile. Size and battery life affect the level of mobility, but the form factor is key. If I must set up shop on a fixed, flat surface to be productive, the device, while portable, is not mobile. Unlike Bob Russell, I differentiate between the two.

WOW! Shout a really obvious and boring statement at us why dont you?

Anyways, I define mobile by size, my usage patterns make battery life irrelevant. I hate the term man bag, but in order to be truly mobile to me it has to be small enough to fit in it at least. My laptop has a 13 inch screen, and its too big to be truly mobile. I guess for me a good rule of thumb is if it can fit in my hand its truly mobile, and it gets bonus points if it can replace at least one other item in my daily gear bag.

IF YOU DO NOT HESITATE TO TAKE IT WITH YOU (AND YOU DO FEEL LIKE YOU ARE GOING TO NEED IT) WHEN YOU ARE GOING OUT, IT IS MOBILE.