Viacom had asked the court for access to the information stored in the logging database as part of a $1 billion copyright infringement lawsuit filed last year against Google and its YouTube LLC video-sharing unit. U.S. District Judge Louis Stanton last week agreed with Viacom's claim that the video-viewing data could help the media and entertainment company "compare the attractiveness" of videos that allegedly infringe on its content copyrights against the appeal of those that don't do so.

Google argued that handing over the data, which also includes user log-in IDs and IP addresses, would enable Viacom to determine what YouTube users are watching and uploading. And Stanton's ruling prompted some privacy advocates to side with Google and criticize the judge for essentially giving Viacom unbridled access to what should be private viewing records.

Although such concerns are legitimate, the whole issue stems from Google's policy of capturing the viewing data, said Marc Rotenberg, executive director of the Electronic Privacy Information Center (EPIC) in Washington. "Google has a business practice of retaining all the search queries of YouTube viewers," Rotenberg said. "It is this practice that puts consumer data at risk."

The end result, he added, "is exactly what were warning about" during a court dispute between Google and the U.S. Department of Justice over Internet search data two years ago.

In that case, the DOJ subpoenaed Google to turn over records on millions of search queries that the government said it needed as part of an effort to defend the Child Online Protection Act from legal challenges. EPIC supported Google's ultimately successful effort to oppose the subpoena, Rotenberg said. But, he added, the privacy group cautioned even then that as part of the discovery proceedings in criminal or civil cases, Google could at any time be asked to turn over users' personal data.

Google's continuing habit of storing highly detailed search data so the information can be analyzed for targeted marketing purposes poses a "real concern" for U.S. residents, Rotenberg said. As the decision in the Viacom case demonstrates, "companies can't always control who has access to this sort of data," he noted.