iPhone Ushers in a New Age

When you stake your future on a big touch screen, you've got to expect a lot of pushback.

Apple (AAPL Quote) isn't the first device maker to ditch -- some might say liberate -- the standard mechanical keyboard in favor of a virtual buttons. But the hotly anticipated iPhone, which is due to go on sale this evening across the nation, marks a make-or-break moment for the technology.

The touch screen opens up a whole new world of utility. Getting the phone's limited surface to serve double duty for input and viewing is brilliant in theory. But as any bank ATM user probably knows, this smudgy innovation can also serve up a whole heap of frustration.

"The biggest disappointment will probably be the virtual keyboard, at least for anyone used to a Treo, BlackBerry or Sidekick," says Peter Rojas, editorial director of tech blog Engadget. ...