A US judge has ordered online video-sharing site YouTube to disclose who watches the website’s video clips and when.
It comes after Viacom and other copyright holders argued they needed the data to show whether their copyright-protected videos are more heavily watched than amateur clips.
Viacom is seeking at least $1bn in damages from Google, which owns YouTube, for alleged copyright infringements.
Judge Louis L Stanton authorised full access to the YouTube logs, which contain the log-in IDs of users, the computer IP address and video clip details.
Although the legal case is taking place in the US, it is believed the ruling will apply to YouTube users and their viewing habits across the globe.
YouTube was bought by Google in 2006.
Google’s senior litigation counsel Catherine Lacavera said in a statement: ‘We are disappointed the court granted Viacom’s over-reaching demand for viewing history.
‘We will ask Viacom to respect users’ privacy and allow us to anonymise the logs before producing them under the court’s order.’
Which? technology editor Matthew Bath said: ‘The US ruling could have huge ramifications for the privacy of consumers.
‘In effect, it would provide a complete list of every YouTube video that every user has ever seen, which in a commercial copyright case seems excessive.
‘Google is right to ask that the US courts grant its request to remove personally identifiable information before the YouTube logs are handed over.’