Legal experts say a recent US court ruling could force the music industry to provide more evidence against people accused of illegal file sharing.

The ruling was handed down in a case filed a year ago against Christopher David Brennan of Waterford, Connecticut, by plaintiffs Atlantic Recording, Electra Entertainment Group, Interscope Records, Sony BMG Music Entertainment and BMG Music.

The record companies allege that Brennan infringed on copyrights they hold by having some 2,071 songs on his PC, including Hootie and the Blowfish's "Drowning" and Billy Joel's "Don't Ask Me Why."

Court records show that Brennan's mother was served a notice that he needed to appear in court, but he never showed up. So the record labels asked for a default judgment, which would have meant Brennan would have to pay the labels for each infringing file, among other remedies.

In their original complaint, filed in US District Court for Connecticut, the record labels alleged that Brennan used an "online media distribution system" to "make...available" copyrighted recordings.

But on 13 February, US District Judge Janet Bond Arterton denied granting a default judgment, writing that the record labels failed to show Brennan was actually distributing copies of songs, which he said is what is against the law.

The record labels' "allegations of infringement lack any factual grounding whatsoever" and adding that the suit has a "nonexistent factual record," Arterton wrote.

Arterton essentially rejected that having songs present on a PC constitutes a violation of copyright, wrote Pamela Jones] on the Groklaw blog. The text of the ruling is available there.

"That seems to be a very significant blow to the RIAA's [Recording Industry Association of America] template litigation strategy," she wrote.

Record labels employ computer forensics companies to observe file-sharing networks and track down file sharers. Once the IP (Internet protocol) address for a computer connected to a file-sharing network has been obtained, the labels have gone to court to force ISPs to identify the subscriber connected with the address.

But privacy activists are increasingly pushing the view that a person's IP address should be private information that should only be revealed during criminal investigations rather than civil ones. Also, they argue the IP address will just reveal the subscriber, not necessarily the person responsible for infringing copyright.

In the Brennan case, it remains to be seen whether the record labels have information that would satisfy the court, wrote Fred von Lohmann, senior staff attorney with the Electronic Frontier Foundation, on the organization's blog.

However, "this ruling suggests that courts are not prepared to simply award default judgements worth tens of thousands of dollars against individuals based on a piece of paper backed by no evidence," von Lohmann wrote.