According to the suit, filed by law firms in Baltimore and San Francisco, an Australian blogger revealed in September 2011 that five Facebook cookies continue to track users' internet browsing after they have left the social media site.
Although Facebook acknowledged the blogger's revelations were true, the company said the tracking was inadvertent and it was not using the information collected. However, Facebook subsequently filed for a U.S. patent related to the tracking technology. In response to queries from government officials, Facebook said it often files to protect its intellectual property, even if it does not intend to use the technology for business purposes.
The suit seeks an injunction that would bar Facebook from installing the cookies in question, and also seeks damages based on whatever profits Facebook made as a result of the tracking.
Facebook has said the case is without merit.
The suit was filed on the same day the White House unveiled a "Consumer Privacy Bill of Rights," which is intended to shore up internet privacy protections.