A federal judge in New York has ordered Google to turn over to Viacom a database linking users of YouTube, the Web's largest video site, with every clip they have watched there.
The order raised concerns among users and privacy advocates that the online video viewing habits of tens of millions of people could be exposed. But Google and Viacom said they were hoping to come up with a way to protect the anonymity of YouTube viewers.
Viacom said the information would be safeguarded by a protective order restricting access to the data to outside advisers, who will use it solely to press Viacom's $1 billion copyright lawsuit against Google.
For every video on YouTube, the judge required Google to turn over to Viacom the login name of every user who watched it and the address of their computer. Both companies have argued that such data cannot be used to unmask the identities of individual users with certainty. But in many cases, technology experts and others have been able to link the addresses to individuals using records of their online activities.