Maybe Apple is coming out with a tablet PC, but it seems unlikely. It's not a product that makes sense. Tablet computers have been available for Windows a couple of years now; they're not selling like gangbusters and there's no reason to assume that a Mac version will do better, no matter how much magic pixie dust Steve Jobs shovels onto the product.

The rumor that Apple is working on a tablet PC is perennial; it comes up again and again. It came up this week.

Blogger Dr. Macenstein is right: The only times you need a tablet is when you're using a computer while standing up, and that's just not something most people do very often. An iPhone, or some other smartphone, nicely fills our on-the-go computing needs if carrying around a notebook computer is impractical.

The real problem with notebooks isn't the keyboard, it's the weight and bulk. A tablet PC is just as bulky and heavy as a notebook, and less usable. There's no real benefit to 'em.

Dr. Macenstein writes: "The entire basis of the Apple tablet rumor seems to be based more in the need of some Apple fans to see it made than to actually use it. There are no longer any technological hurdles to overcome in making a tablet PC, so it is understandable to think, 'why not make one?'"

Indeed, if you build an iPhone with a display bigger than 8", you've got yourself a nice little tablet PC. But why would you want to do that?

The Unofficial Apple Weblog agrees: "The whole ultraportable idea seems to be based on the fact that people want to see it made, not necessarily that anyone is walking around with an iPhone and a MacBook and still asking for yet another computer to carry around."

Dr. Macenstein notes that Apple patented a Mac tablet PC in 2005, and probably "has an 'iTablet' touchscreen portable prototype locked away deep inside its R&D labs," but that doesn't mean that Apple is going to sell them.

How much market share do tablet PCs have, anyway? I'm not sure; the best statistic I've been able to come up with is 1.4% of all mobile PC shipments in 2006. That's an old statistic, and it's secondhand, too, from Gartner by way of a blog. I include it because it jibes with my own experience -- I don't ever see anybody using a tablet PC unless I go to a gadget-friendly conference like the Web 2.0 Summit, or O'Reilly ETech, and even there I'll only see one or two tablets. People just don't use them much.

What do you think? Would lots of people buy Mac tablets? Would you?