The German subsidiaries of Microsoft and eBay are intensifying their collaboration on preventing software piracy, threatening to sue individuals who sell illegally copied software.

"We've been working with eBay since 2002 to track down and prosecute groups and individuals organised as commercial entities that have tried to sell illegal copies of our software over the internet," said Thomas Baumgärtner, a spokesman for Microsoft. "Now we've decided to intensify this cooperation to include private individuals who attempt to sell illegal copies of our software."

The collaboration with eBay is not a corporate-wide initiative but rather an effort by Microsoft's German subsidiary to battle software piracy in a country that, only a few years ago, suffered from one of Europe's highest levels of software piracy, according to Baumgärtner.

Germany's share of illegally copied software dropped 2 percent to 27 percent in 2005, reducing software vendors' estimated loss of revenue by €300m (about £200m) to a total €1.5bn (£1bn), according to the BSA (Business Software Alliance). It was the first drop in software piracy in Germany since the BSA started publishing figures on the German market in 1999.

"We decided it was not enough to go just after commercially organised groups but also private individuals who try to make money on eBay with software they've illegally copied," Baumgärtner said.

Microsoft has taken numerous commercially organised groups to court over software piracy allegations and sued for damages in civil suits, according to Baumgärtner. "Now we plan to do the same with private individuals," he said.

The German subsidiary has a special group of people monitoring the eBay website, looking for possible software pirates and making "test purchases" to confirm product authenticity.

Customers who detect foul play or are concerned that they may have illegal copies can send their products directly to Microsoft's Product Identification Service, Baumgärtner said.