Cheap and tiny subnotebook computers have become, well, ubiquitous. Dell is the latest company to ship one, joining a list that includes ASUS, Acer, Everex, Fujitsu, Hewlett-Packard, Lenovo, LG, MSI and many others.

Subnotebooks are easy to take anywhere, but hard to use once you get there.

Cramped keyboards, tiny screens and undersized touchpads make subnotebooks slow, awkward and difficult to use compared with desktop PCs and even full-size laptops.

Usability is one problem. Performance is another. Loading several simultaneous applications and Web sites can slow down systems with minimal RAM and microprocessors designed more for battery life than for performance.

Enter Ubiquity

Mozilla, the company that makes the popular Firefox browser, announced last week a software plug-in for Firefox called Ubiquity, which does some surprising and useful things.

Ubiquity wasn't designed for, and isn't promoted as, a subnotebook usability enhancer. It's meant to be an all-purpose Firefox booster. But it turns out that Ubiquity is especially powerful on subnotebooks. The reason: Ubiquity replaces the act of opening multiple browser windows or tabs to perform multi-site or multi-page tasks with simple commands that give you the same result.

After installation, launch Ubiquity from Firefox by pressing Ctrl+Space (Option+Space on a Mac), which brings down a command-line menu. You type a command, and the magic happens.

When you type a letter or two, Ubiquity drops down a list of suggestions, of guesses as to what you intend to type. Once you see your intended option on the list, you can stop typing the service and go on to type the rest of the command. For example, let's say you want to find a video demo of Ubiquity on YouTube. You type "y" (without quotation marks), and "Yahoo," "YouTube" and "Yelp" come up on the list. Go ahead and type "o," and YouTube remains as the only option on the list. Leave it at "yo," hit the space bar, and type "ubiquity." Before you hit the enter key, several thumbnails of videos on YouTube pop up, and two of them are Mozilla Ubiquity demos.