Updates to this story
Facebook is to face a class action lawsuit in Canada, one of its biggest markets - and strongest critics.
The suit, filed by Toronto-based Merchant Law Group, accuses the company of changing both its terms of service and users' privacy settings without their assent.
It's looking for damages amounting to the total profits the company made by using the information - so probably quite a lot.
"Facebook shamelessly breached the privacy of people who trusted it, is what this claim asserts," says Tony Merchant QC.
"Everything from naked teenage pictures sent to boyfriends to confidential business and family secrets sent six or ten years ago and likely forgotten now goes into the public domain."
Merchant is one of Canada's most prolific litigators, having notched up thousands of cases in the US as well as Canada. So far, he's signed up around 200 people for the Facebook suit - and is looking for more.
The suit, here, asserts that Facebook knew perfectly well that users would be unwilling to share this information.
Canadians are some of the most enthusiastic Facebookers in the world - over 48 percent of the population are members, says market research firm Inside Network.
But the country has also been one of the most critical of the company's security policies. In July last year, the country's privacy commissioner, Jennifer Stoddart, issued a report slating the company.
Facebook changed its policies to conform with the country's Personal Information and Protection and Electronic Documents Act (PIPEDA). Since then, however, Stoddard has indicated that she still isn't happy, and may open a new investigation.