In computer interfaces, hovering is the familiar behavior that consists of using your mouse to move the cursor to a certain button… but without actually clicking the button. The simple repositioning of your cursor (often referred to as rollover) can cause things to happen, such as the display of pull-down menus.
Funnily, while Steve Jobs has gone to great pains to explain why the Adobe Flash approach has no intrinsic right to be retained in the new iPad context, he has almost totally glossed over the fact that one of the major bugbears in getting websites to run on an iPad is the fact that, on this delightful new gadget, the entire hovering phenomenon is anathema. That's to say, on a touch screen, you can use your finger to simulate the click of a mouse, but there's no way of getting your finger to hover meaningfully over such-and-such a button on a touch screen.
To my mind, this shortcoming is a great pity, since hovering is a most useful technique. Why weren't Apple's design engineers capable of imagining some kind of device that can detect the presence of a hovering finger just above the screen? Even back in the days of Genesis, commentators imagined the Holy Spirit as hovering above the waters. Surely, today, a few millennia later (according to Creationists), it should be possible to invent a technique capable of detecting the presence of a finger hovering above the surface of an iPad.
In any case, it's high time to update Omar Khayyam:
The greasy finger hovers and, having clicked, drags on...