Two Facebook users have sued the social networking site over allegations of perusing private messages to share information with advertisers and marketers – for a profit.

The lawsuit filed in the U.S. Northern District Court of California by Matthew Campbell and Michael Hurley accuses Facebook of systematically scanning nominally private messages to “improve its marketing algorithms and increase its ability to profit from data about Facebook users.” It counts links to other websites in private messages as sort-of “likes” to add to the Facebook user’s web activity profile that advertisers can use.

Such searching, if it is taking place, would violate the Electronic Communications Privacy Act, according to the suit. TIME online quotes Jackie Rooney, a spokeswoman for Facebook, as saying that the allegations are “without merit.”

Facebook is not alone in facing such allegations. Google, Yahoo and LinkedIn have all been accused of intercepting communications for profit, according to Bloomberg.

•Facebook Founder Mark Zukerberg.