Hearkening back to the early days of the Mac OS, Dashboard is a new feature of Tiger that mixes the classic Mac's Desk Accessories with Exposé and a dash of Web savvy to create a whole separate layer of the Mac interface.
Apple bills Dashboard as "Exposé for Widgets," and indeed Dashboard wouldn't make a lot of sense were it not for its integration with Exposé. Essentially, Dashboard lets you run small programs (Apple seems to be calling them "widgets") on an invisible layer within Exposé. When you press a key (by default it's F12), the Dashboard layer zooms and fades in, as if it had been hiding somewhere just behind your head all along.
So what lives on the Dashboard layer? Little things. In other words, don't expect to do your word processing or spreadsheet calculations in Dashboard. But smaller tasks that should only get in your face for a few seconds (like the DAs you used to stash in your Apple menu back in the day) are prime Dashboard territory. Among the applications for Dashboard, according to Apple: a calculator, a quick Address Book look-up, an iTunes controller, a stock ticker, Stickies (but of course), a clock, and a calendar. Fans of the old Puzzle DA will be happy to hear that the winner of last week's Dashboard development contest designed a Dashboard front-end for the Free Software Foundation's unix-based Go game. Can Dashboard chess and checkers be far behind?
A few of Apple's sample widgets were pretty simple, but a lot of fun. The one that displays a live Webcam of your choice is a lot of fun, but it must have been pretty easy to "program" too -- after all, all that widget's really doing is loading an image from the Web in what's essentially a Web browser window. Since writing a Dashboard widget isn't much more complicated than building a Web page, it's safe to assume that once Tiger arrives we'll be seeing a flood of homegrown Dashboard applications. Most of them will be godawful. And a few of them will be incredibly brilliant. I can't wait.
(One final note: the Web's been abuzz with thoughts about how similar Dashboard is to Arlo Rose & Perry Clarke's Konfabulator. Although I don't agree with all of his points, I am generally in agreement with John Gruber's take on the subject. No doubt, Dashboard is going to eat Konfabulator's lunch. But there also seems to be little doubt that calling Dashboard a knock-off of Konfabulator is unfair. If you're curious, give Konfabulator a try and see what you think. If you like it, paying $25 will give you Rose & Clarke's desktop widgets today, rather than waiting for Apple's widgets to arrive in 2005 with Tiger.)