On Thursday, a judge in Northern California District Court turned down Facebook's request for dismissal of a lawsuit which alleges that the social network's photo-tagging feature -- which uses facial-recognition technology -- violates the privacy of users.

In the Thursday ruling, Judge James Donato gave a go-ahead to the lawsuit against Facebook. The lawsuit will move forward under an Illinois law -- the Biometric Information Privacy Act -- which requires companies to seek prior consent from their users for collecting and storing biometric data, including "faceprints."

Since "faceprints" -- geometric representations of an individual's face -- are used by Facebook for identifying people in photos, the key accusation against Facebook is that the creation of "faceprints" by the photo-tagging feature, without explicit consent, underscores a violation of user privacy.

In permitting the lawsuit against Facebook to proceed, Judge Donato said in the Thursday ruling: "The Court accepts as true plaintiffs' allegations that Facebook's face recognition technology involves a scan of face geometry that was done without plaintiffs' consent."

Judge Donato further added that the Biometric Information Privacy Act is "an informed consent privacy law," which chiefly addresses the collection, retention and use of personal biometric identifiers and information at a time when the broad deployment of biometric technology has just begun.