In what some consider to be a landmark decision, the European Court of  Justice ruled Thursday that forcing Internet service providers (ISPs)  to monitor consumer traffic in order to block copyright infringement is  incompatible with European Union laws.
 
 The decision comes as a result of a complaint filed in 2004 by SABAM,  the Belgian association of authors, composers and publishers, against  Scarlet, a telecommunication company and Internet service provider  operating in Belgium and the Netherlands.
 
 SABAM alleged that Scarlet's customers were downloading copyrighted  works without authorization from peer-to-peer networks and sought an  injunction that would force the ISP to prevent the infringement.
 
 The Brussels Court of First Instance granted the injunction and ordered  Scarlet to make it impossible for its customers to send or receive files  from SABAM's portfolio, which would have forced the ISP to monitor the  Internet traffic of all of its customers and build a complex filtering  system from its own resources.
 
 The company appealed the verdict and the Brussels Court of Appeals asked  the European Court of Justice (ECJ) to clarify if such an injunction  would be in violation of E.U. laws.
 
 The ECJ ruled Thursday that imposing an obligation on an ISP to perform general monitoring of  consumer traffic in order to protect the right of intellectual property  is incompatible with the E-Commerce Directive and other individual  rights safeguarded by the E.U. Charter of Fundamental Rights.
 
 First of all, such a system would require the collection and analysis of  content and identification of IP addresses, which is protected personal  data under E.U. law, the court said. Secondly, such a system could be  prone to errors that could result in the blocking of lawful  communications in violation of freedom of information principles, it  added.
 
 "E.U. law precludes an injunction made against an internet service  provider requiring it to install a system for filtering all electronic  communications passing via its services which applies indiscriminately  to all its customers, as a preventive measure, exclusively at its  expense, and for an unlimited period," the ECJ said in a public  statement.
 
 "We regret the ruling," said the CEO of SABAM, Christophe Depreter, in a  phone interview. "We consider that an important door has been closed  for authors and composers in their fight against piracy."
 
 However, Depreter said that there are other methods of combating online  piracy and the organization will consider other actions to enforce the  rights of its members.
 
 SABAM has not taken a decision regarding its legal action against  Scarlet yet and Depreter said that the organization will consult with  lawyers and technicians over its possibilities. Scarlet could not be  reached for comment in time for publication.
 
 The European Commission welcomed the court's clarification that the  E-Commerce Directive prohibits the imposing of a general obligation on  ISPs and other intermediaries to monitor traffic.
 
 The ruling shows the case for promoting legal content alongside  enforcement, said Neelie Kroes, the European Commissioner for Digital  Agenda and Vice-President of the European Commission.
