Over the weekend, Engadget ran a great article about "invisible devices." When Apple introduced the new iPod Nano, (a 1.5 inch square touchscreen device that has several functions including a watch) the internet immediately began clamoring for the Nano as a wristwatch. Manufacturers are rushing Nano watch-bands to market. Even though the Nano wasn't intended to be used as a wristwatch—it's not waterproof, for one thing, and what good is a watch you have to charge every day?—Apple unintentionally tapped into a market that nobody knew existed. You should read the whole article, but here's the basic point:

Invisible devices like watches are the digital equivalent of undeveloped beachfront property. It's there and available but it's being ignored. The power of the invisible is that it frees up space for other gadgets users might want to carry — and most people will carry more than one invisible device.This in turn, creates a wonderful gap that is not yet being exploited by vendors: an iPod that doubles as watch means there's now one more visible device I can carry.