If Apple (NASDAQ:AAPL) isn't going to deliver the tablet computer that everyone is expecting, leave it to Hewlett-Packard (NYSE:HPQ) to crash the hype party.

HP introduced its DreamScreen line of flat Wi-Fi-enabled devices this morning.

They're slick and attractively priced -- at $249 for the 10-inch screen and $299 for the 13-inch model.

On the downside, they don't do as much as they should. The DreamScreen is essentially a glorified digital photo frame with multimedia goodies and very limited online connectivity. Users can stream photos, music, and video located elsewhere in their home networks or stored in the 2 gigabytes of internal capacity. They can also access Facebook, Pandora, and HP's own Snapfish. That's pretty much it, though.

What good is a portable Wi-Fi screen if it can't access Google's (NASDAQ:GOOG) YouTube and other video-sharing sites? It's easy to see why HP would back Snapfish as a photo-sharing platform, but it leaves out the obvious Shutterfly (NASDAQ:SFLY) and Yahoo!'s (NASDAQ:YHOO) Flickr.

The DreamScreen also accesses HP SmartRadio, a new hub that offers free access to 10,000 Internet radio stations. Along with Pandora connectivity, this would be a threat to Sirius XM Radio (NASDAQ:SIRI) if it weren't already retreating from the home market. Satellite radio's growth has come primarily from factory-installed car models lately.

In short, HP's new device does a few things well, but it doesn't replace the netbook the way that Apple's inevitable device will. The DreamScreen isn't an email retriever or a gateway to even primitive computing tasks.

It also doesn't offer a touchscreen or a keyboard, so even access to Facebook is unlikely to be as interactive an experience as some may expect.

HP is positioning this as a "fourth screen" for consumers, with computer monitors, televisions, and smartphones being the first three. It's a noble concept, but sadly incomplete. We need more, HP. We will be willing to pay more, too.

Fourth screen? I plead the fifth.

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Longtime Fool contributor Rick Munarriz is a subscriber to both Sirius and XM. He owns no shares in any of the companies in this story and is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance. The Fool has a disclosure policy.