Washington ? Hollywood and the music industry can file piracy lawsuits against technology companies caught encouraging customers to steal music and movies over the Internet, the Supreme Court ruled Monday.

The justices, aiming to curtail what they called a “staggering” volume of piracy online, largely set aside concerns that new lawsuits would inhibit technology companies from developing the next iPod or other high-tech gadgets or services.

The unanimous ruling is expected to have little immediate impact on consumers, though critics said it could lead companies to include digital locks to discourage illegal behavior.

The justices left in place legal protections for companies that merely learn customers might be using products for illegal purposes.

The justices said copying digital files such as movies, music or software programs “threatens copyright holders as never before” because it’s so easy and popular, especially among young people. Entertainment companies maintain that online thieves trade 2.6 billion songs, movies and other digital files each month.

“I am pleased that the Supreme Court has considered this important case and determined that those who intentionally induce or encourage the theft of copyrighted music, movies, software or other protected works may be held liable for their actions,” Atty. Gen. Alberto Gonzales said.

The ruling represents a significant victory for Hollywood and record labels, which have resorted to suing individually the thousands of computer users caught sharing music and movies online.

The court said Grokster Ltd. and Streamcast Networks Inc., developers of leading Internet file-sharing software, can be sued because they deliberately encouraged customers to download copyrighted files illegally so they could build a larger audience and sell more advertising.