The days of unrestricted Rox-MP3-sharing over the internet appear to be over. In fact, if you run a search for “Roxette” on Napster, the result will be “No matches found.”

  Napster has stated its intention to filter out all copyrighted material – without regard to artist or record company – from their servers so that users will not be able to view, search or share copyrighted material.

  Some Napster alternatives have already begun to install similar filters while others appear to be on the road to closure.

  The great Napster migration has begun, as users slowly leave the file-trading service because of the drop in songs available on the network. Meanwhile, the company continues to fight for its life in U.S. federal court.

  To the recording industry that has fought with loaded guns to shut the system down, however, Napster – and free, indiscriminate digital music sharing – is already history.

  “Emotionally, Napster is over,” Recording Industry Association of America head Hilary Rosen said Tuesday. “We’ve moved on already.”

  And so have the music traders.

  In April, Napster use fell by nearly 36 percent from the previous month, according to a study released by the Webnoize research department. The main cause: a drastic decline in the number of files being made available on the system, in part due to the improved filtering technology employed by the company.

  The average number of songs available by individual users dropped from its all-time high in March of 220 down to a paltry 37 by the end of April. That led to nearly 1 billion fewer downloads.

  Not surprisingly, the radical shift in file trading has discouraged many users from logging on to the service.

  “Some users are walking away from Napster and gravitating to alternative systems,” Webnoize senior analyst Matt Bailey said in a statement. “Many others are walking away from the file sharing altogether.”

  In March, federal district Judge Marilyn Hall Patel granted the recording industry an injunction that required Napster to begin filtering copyrighted songs from its file-trading directory.