Facebook(s fb) is facing a new class action lawsuit that accuses the social network of violating state and federal privacy laws by scanning the content of users’ private messages in order to obtain advertising data.

In a complaint filed Monday in San Francisco, two men claim the company is surreptitiously scanning messages in order to detect websites that Facebook users send to one another in private. The purpose of the scanning is allegedly to increase the number of “Likes” to those websites, and in turn make Facebook more popular with advertisers.

The lawsuit cites recent research by a Swiss security firm that disclosed that the number of “Likes” on a web page goes up whenever a Facebook users send the page as a private link — proof, in other words, that Facebook has not been truthful in stating that such messages are only viewed by the sender and recipient. The company…