Ever since the Apple iPhone arrived more than three years ago, gadget makers of all kinds got busy replacing real buttons with virtual ones on touchscreens. A gazillion gadgets conspicuously touting touch have emerged in recent months in an attempt to benefit from warm-and-fuzzy feelings consumers have developed for Apple multitouch devices.

Marketers are preying on consumer naiveté. By emphasising touch screens, they suggest that their products are part of the new generation of devices represented by Apple's iPhone and iPad. But touch alone isn't what the new generation is all about. Here's what you need to know.

What's so great about MPG?

The ability to touch a screen and have a system respond is not what's great about Apple iOS devices like the iPhone and the iPad. What's great about iOS gadgets is that they have multitouch, physics and gestures (MPG) together as an integrated user interface experience.

This combination of features is what Steve Jobs called "magical" (to the derision of critics). And I certainly wouldn't use that word. But what's happening is something of an illusion. But it's not an optical illusion.

By combining multitouch with physics and gestures, MPG devices create the illusion that the virtual stuff on screen is physical. Your mind accepts the physicality of the nonphysical on-screen objects, which gives you a feeling of power and control that's a little thrilling and maybe even a little addictive. MPG taps into your brain's hardwiring for how the world should work, something mouse-based PCs don't do, and something old-fashioned kiosk-style touchscreens don't do.

What you need to know is that many of the new gadgets advertised as "touchscreen" devices offer nothing more than old, kiosk-style poke-at-the-onscreen-button interfaces.

The difference between a real MPG touchscreen interface and an old school touchscreen is like the difference between riding the Nitro roller coaster at Six Flags Great Adventure and riding the tram to get from the parking lot to the entrance to the park. It's like the difference between surfing and watching a video of somebody else surfing. It's like the difference between flying an airplane and playing Microsoft Flight.

One is just a flat, distant and abstract experience, and the other satisfies your deepest intuition about how the physical world should work.

That's why it's absurd that gadget makers selling ordinary touch screens push basic touch interfaces as somehow in the same class as the interfaces of MPG devices. They're opposites. Touch screens represent the past, while MPG devices represent the future.