Called Opera Unite, the technology allows users to transform their computers into machines capable of hosting Web sites, blogs, and just about anything that’s usually placed on a third-party server.

Like file-sharing. However, the Oslo-based Opera company says the file-sharing feature is for you to exchange files with friends rather than share content with the entire world. Whether the entertainment industry is going to be happy with this feature probably depends on just how many “friends” Opera Unite can share files with.

According to the company, users designate the directory they wish to share with their buddies and Opera Unite generates a direct URL to that directory for distribution to others. While sending that URL to a few close friends is unlikely to cause any infringement concerns, it’s easy to imagine mailing lists consisting of hundreds of thousands of potential downloaders waiting for that specific URL.

Along with file swapping, Opera Unite also provides a media player enabling users to listen to their private digital music stash wherever they may be. Other features include “The Lounge” – a self-contained chat service you can run on your computer, and “Fridge,” which gives users a virtual refrigerator for posting notes.

While Opera Unite may be full of whiz-bang whistles and bells, as soon as the company announced the new technology, tech bloggers cited possible security problems as well as local area network (LAN) issues. With internal corporate networks often experiencing congestion problems, it’s easy to speculate as to how those problems might grow if individual computers become Web servers.

But those security concerns are based on how writers think Opera Unite may work, and are not necessarily descriptive of how the technology actually performs in the real world. Plus, when you consider how Internet technology in general often focuses on providing individual users with more power, turning desktop computers into servers is a concept that would eventually have become reality – with or without Opera Unite.

“With sever capability in the browser, Web developers can create Web applications with profound ease,” said Opera CEO Jon von Tetzchner. “Consumers have the flexibility to choose private and efficient ways of sharing information. We believe Opera Unite is one of our most significant innovations yet, because it changes forever the fundamental fabric of the Web.”

Click here for the Opera Web site.