Ubiquity is a Firefox extension that works in Windows and OS X (Linux support is still incomplete). Install it, and you can call it up by typing <Ctrl><Space> in Windows or <Option><Space> on a Mac. What you get is a window that pops up above the Web page you’re on in Firefox, with a command line that you can type natura-language commands into.

Type Google and one or more keywords, for instance, and Ubiquity will Google for you, previewing the first few links and letting you press <Return> to go to Google’s results for the words you searched for:

Type Map and an address, and you get a Google Maps preview; press <Return> to go to Google Maps…

Type Weather and a city, and you get…well, you know:

Ubiquity is an open platform that Web service providers can add their services to; already, it includes support for an array of ‘em, including Google, Yahoo, YouTube, Yelp, Wikipedia, TinyURL, Gmail, and a bunch more. If you’re a Twitter addict, you can Tweet from Ubiquity:

In a way that’s reminiscent of the Greasemonkey extension, Ubiquity can modify Web pages on the fly. For instance, if you highlight an address on a page, call up Ubiquity, type Map, and then choose to insert the map in the current Web page, you can turn this snippet of Google’s “Contact Us” page…

…into this:

(This is a nifty effect; I’m trying to think of instances where it might be useful, though…and coming up a bit short.)

Besides the command line, Ubiquity has a context-sensitive menu that you can bring up by highlighting information on a Web page and then doing a right-click. You can use this to translate information from one language to another, for example:

Ubiquity already has a pretty extensive bag of tricks, but Raskin says the real goal is to make it capable of doing extremely sophisticated natural-language mashups that let users take advantage of multiple Web sites and services without ever leaving the Ubiquity window. Here’s his mockup of a fancy travel command:

So what’s my initial take on Ubiquity? Mozilla calls it an experiment, and that seems about right: It’s a neat idea that’s worth exploring. It’ll be interesting to see whether it appeals mostly to nerds–as command-line approaches to computing have for the last fifteen or twenty years–or has more widespread appeal. I know I’m going to leave it installed and try out it out…and will keep an eye on it to see how it evolves.