Government regulators are sharing some alarming information about Facebook: They believe the online social network has often misled its more than 800 million users about the sanctity of their personal information.

The unflattering portrait of Facebook’s privacy practices emerged last week in a Federal Trade Commission complaint alleging that Facebook exposed details about users’ lives without getting legally required consent. In some cases, the FTC charged, Facebook allowed potentially sensitive details to be passed along to advertisers and software developers prowling for customers.