NEW YORK (Reuters) - As personal computers go, the new rash of ultra-mini laptops are full of geeky goodness. Light, portable and powerful, they are almost perfect. Almost.

But like a rowboat in your backyard or a flat-screen TV in a blackout, most of these new PCs suffer when removed from a critical element. Specifically -- when outside of high-speed Internet access range, they go from power-in-your-pocket to pricey-digital scratchpads.

The idea behind the resurgent "netbook" niche is that consumers-on-the-go primarily use computers to email, write documents, manage spreadsheets and surf the Web. Once online, they can access critical files, chat with others, or use social sites like Facebook or music services like Pandora.

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That's great -- if you are sure to be near a broadband connection, such as a home network, a Wi-Fi-covered college campus or an area with WiMax, a high-speed wireless technology that can blanket entire cities.

But an unconnected machine's power is limited.

"I am convinced this class of products will sing when WiMax comes out," said Rob Enderle, principal analyst at The Enderle Group. "It kind of depends on ... being always connected. As a disconnected device, outside of email and word processing, it's not quite as interesting.

"It's more focused on the future than on the present."

By eschewing video editing, the ability to play DVDs, or power gaming, these users forgo the need for cutting-edge chip speed or tons of hard-drive storage capacity, and the extra cost they require.

The latest in this genre is Dell's Inspiron Mini 9, a 2-pound machine with a 9-inch screen and wireless Internet card. At $349, it is similar to rivals developed by Hewlett-Packard, Acer, ASUS, Intel and others aiming at youngsters who prefer a full screen and keyboard to thumbing on smartphones.

With U.S. consumers watching their wallets amid economic uncertainty, the low prices may pique their interest.

"We think that price is ... affordable," said John Thode, a vice president at Dell. "We find that that is the right kind of price to encourage (the purchase of) second and third devices in a person's portfolio."