Napster is facing a new threat to its existence, not from the major record labels, but from companies setting up music-sharing sites.

The incredible popularity of the music-trading service is spawning several new sites every week, and sometimes more. Often, there's something approaching arrogance in the way these newcomers distance themselves from Napster –they try to cash in on Napster's customer base, while ducking its legal troubles, according to observers.

"By ingeniously using technology that maximizes existing technology... has accomplished what copycat sites only dream of," barks, a service that lets users stream music from their hard drives, but, unlike Napster, prohibits actually copying the files.

Legal safety plays a similar game. The company claims: "Welcome to, where you don't need to worry about being sued whenever you download a song." The site claims to use the "honour system", and as with shareware, you are encouraged to pay a small fee to each artist – but only if you keep the MP3 for more than 30 days. The problem? Only a handful of artists are on the site, unlike the terabytes of music on Napster, Scour, and many others.

How many others? I've test-driven 15 music-sharing sites in the last month, from Aimster to XNapster. Some require a client download, and some are Web based. But they all want to help you find and listen to music over the Internet.

Sites are sorting into several categories. First is the Napster clone. These include Scour – which is still operating, but recently filed for bankruptcy – and IMesh. These tools are similar in look and function. Both Scour and Napster are being sued by the Recording Industry Association of America.

Traffic trouble Each of these music services has an enormous customer base, and all three suffer from near-crippling traffic at various times of day. Napster experienced a spike in traffic when a court ruling or injunction was imminent; some competitors also enjoyed an upsurge.

Other services offer direct, peer-to-peer interaction between users, without using a central server as Napster does. These include Gnutella and non-Mac FreeNet. They also offer interfaces that only a programmer could love.

Finally, several music sites offer wares through a Web-based interface. These services may also provide a client for you to download and install, but much of their appeal is in the capability to search the contents of customers' hard drives, right from the Web, as if you were using an old-fashioned search engine. These sites include IMesh (which also has a client download) and Surfy (which lets you search the Web, Gnutella, and Napster from its site).

Protected Some argue that unlike Napster, Web-based music search services receive special protection under the Digital Millennium Copyright Act. That's because it is nearly impossible to monitor or review the information to which they link, says Kurt Opsahl, an Internet-law expert with Perkins Coie.

Opsahl says: "It is still too early to sound the death knell for peer-to-peer MP3 sharing technologies. Congress provided this safe harbor, because they wanted to provide protection so that the information-location industry could provide this useful service."

And while these services claim to succeed where Napster fails, a problem remains. Whether you love or hate Napster, it's hard to deny that few of its musical competitors offer as robust an interface, whether on your PC or via the Web.

So among this crowded chorus of Napster wannabes, do any provide a hearty and intuitive service that appeals to customers but avoids the wrath of the record industry?

Eric Scheirer, an analyst at Forrester Research, says: "No, not right now. The service consumers want is not what the record labels are currently able to provide. Anybody who is satisfying consumer demand will have to be doing it outside of the sphere of the record labels."