Last year the proportion of American households owning computers finally passed 50 percent--leaving more than 130 million people who aren't selling junk on eBay or passing on e-mail jokes to all their friends and acquaintances.

While $600 home computers have lowered the financial costs of entry to the online world, the psychological costs--the complexity and bugginess of any PC--remain serious obstacles. For these acronym-phobic folks, the industry has a new one to offer: IPAD, short for Internet personal access device. IPADs are built to give someone with zero computer experience simple, un-threatening access to the Web and e-mail--and nothing else. Unlike Microsoft's WebTV--the first real Internet-without-a-computer gadget--they don't even require you to plug anything into your other electronic gear.

But simple can be just simplistic, too, as we found out when we tried out two of these "Internet appliances" at home--the i-Opener and the E-mail PostBox. (A third device, Cidco's MailStation, did not arrive in time for our deadline.)

The i-Opener, developed by Austin-based Netpliance (http://www.netpliance.com), is the current leader, at least in terms of ads on TV. It's a $199, two-piece unit, weighing under five pounds, that consists of a sleek 10-inch LCD screen with integrated speakers and an attached full-size keyboard. It comes with only two Internet-access plans: basic ($21.99 a month), which provides unlimited use, an e-mail account and a customizable Web portal, and premium ($26.99 a month), which also provides dial-up Internet access for an existing computer. I-Openers aren't sold in traditional computer stores; they're available through mail order (1-888-467-3637) and are also being sold in selected shopping-mall kiosks (the closest in the Washington area is at the Galleria at Tysons II).

One of the biggest selling points here is that Netpliance configures an I-Opener for the customer when it's ordered, so the machine arrives preconfigured with the right local access number and e-mail address. You can have the i-Opener powered up and online within five minutes of opening the box without even having to read the simple instruction manual.

The passive-matrix screen is bright and adequately sharp, a bit pixelated when trying to read small type but certainly adequate for casual use. Other features include a USB port (currently unusable) and an indicator light that tells you when you have new mail. There's also a parallel port for the one currently supported printer, a $100 Canon color inkjet, plus a PS/2 port for an optional mouse.

The keyboard's dedicated hot keys help you to fetch your e-mail, get caught up on the international news (you can even listen to music or the BBC on streaming audio on the tinny built-in speakers), obtain Zip-code-based local weather information, shop online and get to know the Web in general. Valuable features, yes, but there's one hot key that's nothing short of brilliant--the pizza key, with its pie-shaped logo. One press of this connects you to the Papa John's Pizza Web site, where you can order the ultimate computer accessory--an extra large with everything. (Note to Netpliance: How about including Armand's while you're at it?)

But after the first rush of enthusiasm, the i-Opener's limitations become apparent. Unless you purchase the $20 optional mouse, you're stuck with a laptop-style tracking device that's slow and clumsy to operate; the e-mail system doesn't accept attachments, not even photos; you can't listen to MP3 audio files. (Granted, these constraints will probably be meaningless to many I-Opener purchasers.) And the monthly rates seem a bit steep for this sort of no-brainer service, in which Netpliance's tech-support costs should approach zero.

Who's buying? Netpliance spokeswoman Sharon Gorman said that while many buyers were simply intimidated by computers, others already owned a computer and wanted a second form of Internet access. The latter group includes parents looking to keep their kids off the regular computer, people in need of basic Web access in the kitchen and vacation-home owners who can pay for an account only during the months they're at their beach house or ski house. (Unfortunately, there's no way to use this thing with an existing Internet account.)

If you're interested only in e-mail, VTech (http://www.vtechworld.com), a company best known for its cordless phones, simplifies things even further with its $100 E-Mail PostBox, which offers only e-mail service. This device includes a normal-size keyboard, plus a petite, eight-line LCD mounted atop it; it looks a little like those stand-alone word processors that roamed the earth in the late '80s. But that tiny screen means this machine is useful for reading and writing only succinct notes, not long missives.

Like the i-Opener, the PostBox couldn't be easier to use; large yellow keys labeled "Write Message," "Send and Receive," "Address Book" and so on ensure that even the most dedicated technophobe can send an e-mail. And the access is cheap enough; $89.99 a year, or $24.99 a quarter, lets you use up to five e-mail accounts on one PostBox.

The bottom line: These Web terminals are unobtrusive, not too expensive and refreshingly simple to operate. If you still don't own a computer--and don't think you'll ever use one to do your taxes, design a home or write the great American novel (none of these units has a spell checker, a choice of fonts or formatting options)--these units may be worth considering.

The fact is, a great many people who presently own expensive, space-intensive computers don't really do anything other than surf the Net and communicate through e-mail.

That's the theory, at least, and it's promising enough for many other contenders to be planning their own Internet appliances. Even Microsoft is joining in, with plans for a lineup of "Web Companions" running a vastly simplified version of its Windows CE operating system. Meaning: Your choices are only going to get more complex from here on in.

CAPTION: Netpliance's i-Opener does the Web, but not Windows.

CAPTION: VTech's E-mail PostBox: The write stuff?