There's a dirty little secret a lot of people in the computer industry don't want you to know about your netbook. Are you alone? Good. Now here it is: It's really just a PC.

Okay, stop laughing. You knew that, of course. That's why you bought the thing. The problem: The companies designing, building and selling these suckers don't know you know that.

In Pictures/In Depth:

• 10 Tricks For Pimping Your Netbook
• 10 Mini 'Netbooks' You Can Take Anywhere
• Nine Gadgets That Won't Bust Your Budget
• 10 Cool CES Gadgets
• 10 Cool NASA-Inspired Technologies

Many computer manufacturers are hoping these low-cost laptops won't hurt the margins they like to get on their fuller-featured machines. Tough luck. Research analyst Gartner predicts sales of low-cost netbooks will double to 21 million units in 2009 from 11.7 million units last year. Overall PC sales, by contrast, are expected to fall 9.2 per cent.

And netbooks are growing more capable, even as they continue to fall in price. "People love them because they are usable PCs for a lot of purposes," says Gordon Haff, Gordon Haff, principal IT advisor at Illuminata, in Nashua, N.H.

While PC makers will tell you netbooks are much less capable than, say, a quad-core desktop processor with dual graphics cards and 8 gigs of memory, if you measure a machine's capability by how much mischief it can get you into, then you may not be able to find a better machine on the market.

Wired.com found this out the when its editors posted a video showing readers how to boot Apple's OS X operating system onto one of Dell's US$279 Mini 9 netbooks. While Apple's machines are pricey, the software ran just fine on the dinky Dell. The problem: Apple wasn't happy with Wired.com's little stunt. It asked Wired.com to remove the video. Wired.com complied.

No one will complain if you install Linux, however. While many netbooks come with stripped-down, user-friendly variations of the software, full-blown Linux will work just fine on the tiny machines. Even if you're not a master geek, you probably have a friend or two who can help out and fix any nagging glitches you might encounter.

Few people are interested in installing an operating system onto a computer just for the joy of, say, using a particular operating system. The real attraction of netbooks is that just like the PCs of the past decade, netbooks have the power and flexibility to let you navigate your way through the Internet ether and have some fun. For example, you can download file-sharing software and steal music and movies--something you can't do so easily from, say, an iPod touch.

Of course, if you're looking for a cutting-edge performance demon, look elsewhere (and start saving your money too). Take the Dell Mini 9. Its 1.6-GHz Intel Atom processor and 1 GB of memory are fine for e-mail and Web surfing. Its specs are on par with, say, a six-year-old Dell Latitude. The older laptop, however, will come with a capacious mechanical hard drive, rather than the smaller, lighter 4 GB solid state drive you'll find on the standard Mini.

For some, however, those stripped-down specs are just a starting point. Users are also adding GPS chips, wireless cards, TV tuners and touch screens to their netbook gear. This can get tricky: Installing a touch screen, for example, involves cracking open the netbook's case, adding a touch-screen panel to your machine and wiring in a special controller. Another option: Companies such as Winter Computer Soutions will be happy to modify your netbook for you.

To be sure, netbooks won't replace smart phones, cameras or music players anytime soon. "The converged device is never going to be as good at some of the individual functions as a stand-alone device," Haff says. But unlike such purpose-built gadgets, netbooks will work with a huge grab bag of off-the-shelf parts. The only limit is your ingenuity.

One caveat: Many such modifications are for advanced users only. Like when cracking open your notebook computer, be ready to void your warranty and know enough to fix anything you may break while you're poking around.