Having successfully forced file-sharing rogue Napster to comply with copyright laws, the Recording Industry Association of America, along with the major Hollywood studios, is now launching attacks against other popular file-swapping services. MusicCity, Kazaa, Morpheus and Grokster are all being sued, an RIAA representative confirmed yesterday.

"We cannot sit idly by while these services continue to operate illegally, especially at a time when new legitimate services are being launched," Hilary Rosen, RIAA president and chief executive, said in a statement.

The RIAA and the Motion Picture Association of America filed suit against MusicCity.com, MusicCity Networks (which operates Morpheus), Grokster and Consumer Empowerment (also known as FastTrack, operator of the Kazaa service) in the US District Court for the Central District of California late on Tuesday for copyright infringement.

None of the defendants was immediately available for comment yesterday.

Like Napster, the services covered in the suit allowed users to swap content, including copyright-protected music and movies, for free via their networks.

The plaintiffs said the file-sharing networks "created a 21st century pirated bazaar where the unlawful exchange of protected materials takes place across the vast expanses of the internet and where the materials being exchanged include first-run movies currently playing in theatres and hit songs from virtually every major recording artist".

All the peer-to-peer networks charged in the suit use Amsterdam-based FastTrack’s software. FastTrack is a loose organisation of programmers whose services are wildly popular. According to FastTrack, over 34 million copies of its software have been downloaded in the past six months.

What's more, digital entertainment researcher Webnoize reported yesterday that consumers downloaded more than 1.5 billion digital files using the FastTrack network during September.

With the boom in file-swapping and the proliferation of post-Napster progeny, the RIAA and MPAA feel seriously threatened. Much like Napster, the rogue services now being targeted are likely to settle out of court.