US software company SCO has shut down its German website following a court injunction won by German Linux advocacy group LinuxTag.

LinuxTag obtained a temporary restraining order against www.caldera.de following SCO's unspecified claims that Linux infringed its trademarks. An SCO spokesman said the company was being cautious by pulling down the entire site to make sure it did not breach the court order.

The move is just the latest round in a fight over the open-source software. In the first round, SCO sent a letter to 1,500 companies worldwide warning them that Linux infringed its trademarks by incorporating Unix code that it had rights over.

The move was clearly aimed at unsettling companies thinking of incorporating Linux into their business since there was the possibility of subsequent royalties if the case were successful.

However, irritated by SCO's failure to provide any evidence of the claim, LinuxTag went to court on 23 May claiming that SCO was engaging in unfair competitive practices. It gave the company until 30 May to show its hand. SCO failed to give further details of the claim and removed a copy of the letter sent out from its website. However, LinuxTag's subsequent injunction saw the entire site pulled.

Nevertheless, SCO still claims it will fight its corner and LinuxTag's court order is only a temporary victory, with research group Gartner actually advising companies this week to restrict their implementation of Linux until the legal fight is over.

Experts are not convinced by SCO claims and the company is currently on the back foot with Novell threatening to play SCO at its own game, arguing that it does not even own the trademarks that are apparently being infringed. Added to the news last week that Munich city council had decided to switch entirely to Linux, and the case against Linux is looking weak. The fight is still far from over however.

The SCO case is just a warm-up match to the big fight that is currently going on in and around the EC over software patents though. In the 1970s, software was singled out as being free from trademarks in Europe. Since then, pressure has been building to change the law to include it. A concerted three-year campaign has finally seen it put on the EC's agenda to be discussed in the next few months.

The argument for making software trademarkable is that the US and Japanese systems already allow it and so world harmonisation would aid everyone; and that by allowing protection of ideas, trademarking encourages innovation.

The arguments against it are that the existing system already allows significant software trademarking; that it will benefit only big companies; and innovation will actually be stifled.

However, the main concern of Linux supporters is that if trademarking was allowed, big companies with large vested interests would abuse the law to force out open source software through ruinous legal fees.

Claims by Linux advocates that the reason this hasn't happened already is because big companies are waiting to see what Europe decides first may look paranoid, but with SCO already causing significant problems simply by threatening to go to court, there seems little doubt that the open source community will face far tougher fights if the EC decides to extend trademark law.