Internet law professor Michael Geist examines a legal row which could have grave implications for anyone and everyone serving an online audience.

In February 2006, a part-time Canadian music student established a modest, non-commercial website that used collaborative wiki tools, such as those used by Wikipedia, to create an online library of public domain musical scores.

Within a matter of months, the International Music Score Library Project (IMSLP) featured more than 1,000 musical scores for which the copyright had expired in Canada.

Within two years - without any funding, sponsorship or promotion - the site had become the largest public domain music score library on the internet, generating a million hits per day, featuring over 15,000 scores by over 1,000 composers, and adding 2,000 new scores each month.

In mid-October this year the IMSLP disappeared from the internet.

Universal Edition, an Austrian music publisher, retained a Canadian law firm to demand that the site block European users from accessing certain works and from adding new scores for which the copyright had not expired in Europe.

The company noted that while the music scores entered the public domain in Canada 50 years after a composer's death, Europe's copyright term is 20 years longer.

The legal demand led to many sleepless nights as the student struggled with the prospect of liability for activity that is perfectly lawful in Canada.

The site had been very careful about copyright compliance, establishing a review system by experienced administrators who would only post new music scores that were clearly in the Canadian public domain.

Notwithstanding those efforts, on 19 October, the law firm's stated deadline, the student took the world's best public domain music scores site offline.

While the site may resurface - at least one volunteer group has offered to host it - the case places the spotlight on the compliance challenges for websites facing competing legal requirements.

There is little doubt that the site was compliant with Canadian law.

Not only is there no obligation to block non-Canadian visitors, but the Supreme Court of Canada has ruled that sites such as IMSLP are entitled to presume that they are being used in a lawful manner. The site would therefore not be subject to claims that it authorised infringement.

Further, while there have been some suggestions that the site also hosted works that were not in the Canadian public domain, Universal Edition never bothered to provide the IMSLP with a complete list of allegedly infringing works.

Although IMSLP is on safe ground under Canadian law, the European perspective on the issue is more complicated.

There is no question that some of the site's music scores would infringe European copyright law if sold or distributed in Europe. However, the IMSLP had no real or substantial connection - the defining standard for jurisdiction - with Europe.

Indeed, if Universal Edition were to file a lawsuit in Austria, it is entirely possible that the Austrian court would dismiss it on the grounds that it cannot assert jurisdiction over the Canadian-based site.

And even if it did assert jurisdiction, it is unlikely that a Canadian court would uphold the judgment.

This case is enormously important from a public-domain perspective.

If Universal Edition is correct, then the public domain becomes an offline concept, since posting works online would immediately result in the longest copyright term applying on a global basis.

Moreover, there are even broader implications for online businesses. According to Universal Edition, businesses must comply both with their local laws and with the requirements of any other jurisdiction where their site is accessible - in other words, the laws of virtually every country on earth.

It is safe to say that e-commerce would grind to a halt under that standard since few organisations can realistically comply with hundreds of foreign laws.

Thousands of music aficionados are rooting for the IMSLP in this dispute. They ought to be joined by anyone with an interest in a robust public domain and a viable e-commerce marketplace.

Michael Geist holds the Canada Research Chair in Internet and E-commerce Law at the University of Ottawa, Faculty of Law. He can be reached at mgeist@uottawa.ca or online at www.michaelgeist.ca.