A new lawsuit consolidating several complaints about Facebook's privacy policies was filed Friday in California, seeking damages for US users of the social network for improper tracking.
The class action suit alleges that Facebook was improperly tracking Internet use of its members even after they logged out of their accounts.
It consolidates 21 related cases filed in more than a dozen states in 2011 and early 2012.
The filing came as Facebook launched its market debut with a record public offering worth $16 billion, valuing the world's biggest social network at $104 billion.
Lawyers in the suit seek up to $10,000 for each Facebook user, or more than $15 billion.
"It's not a pipe dream," attorney Billy Murphy of Baltimore, Maryland, told AFP.
"The only way you are going to stop companies from disregarding the privacy rights of the American people is to take some of their money. That's the only thing that gets their attention."
But some consumer and privacy advocates say Facebook has been too loose with data from its 900 million users around the world, and hope that as a publicly traded company after its initial public offering, it may change its tune.
Facebook has been bedeviled by privacy complaints and had its knuckles rapped over the issue by both US and European authorities.
The social networking giant's co-founder Mark Zuckerberg has repeatedly apologized for privacy lapses amid outrage from users over revelations their online activities were visible to a wide audience of advertisers and other users.
Late last year, in a settlement with the US Federal Trade Commission, Facebook promised to honor users' privacy preferences and to stop making claims about the security of personal information that are untrue.
That deal settled two-year-old accusations that Facebook had allowed advertisers access to the community's personal data when users were told it was being kept private.