[j.p.s]

Originally Posted by Noughty

Actually, you might not need to move your thumb. It depends on what kind of touch screen it is. I only know two kinds (don't know how the technology differs), one reacts to touch (iphone) so you'll need to move your finger. Another is like nokia - you need to slightly press, so you don't need to move thumb, you can hold it on the screen and slightly press when needed.

I have no idea which touchscreen this kindle have and would like to know. The later option sounds better for an ereader.

It's a third kind. When something such as your finger blocks an infrared beam, the device registers a "touch" at that point. This is better than the press method, because the display is not degraded by the touch layer.