Facebook has sued a data analytics company that operated apps on the Facebook platform for nearly a decade, saying the company misused Facebook data to sell advertising and marketing services. Facebook filed the lawsuit on Friday against Rankwave, a South Korean company, in California Superior Court for the County of San Mateo.

Facebook also suspended Rankwave and its apps from its platform, but Rankwave apparently still has a trove of Facebook user data. Facebook's lawsuit seeks a court order requiring the company to delete Facebook user data and suggests that Rankwave may have sold the user data to other unidentified entities. Rankwave refused to tell Facebook which entities it sold data to and refused to "[p]rovide a full accounting of Facebook user data in its possession," Facebook says.

"Rankwave is an application developer that breached its contract with Facebook by violating Facebook's policies and California law," Facebook's lawsuit alleged. Rankwave has developed and operated apps on the Facebook platform since 2010 and "used the Facebook data associated with Rankwave's apps to create and sell advertising and marketing analytics and models—which violated Facebook's policies and terms," the lawsuit said.

Rankwave also "failed to comply with Facebook's requests for proof of Rankwave's compliance with Facebook policies, including an audit," Facebook alleged. "These actions are prohibited by Facebook's policies, by which Defendant contractually agreed to abide."

The lawsuit has fueled speculation that Facebook is dealing with another problem similar to Cambridge Analytica, in which up to 87 million users' information was improperly shared with a political consulting firm that did work for Donald Trump's presidential campaign. The Cambridge Analytica scandal triggered a Federal Trade Commission investigation into Facebook that could result in Facebook paying a multibillion-dollar fine.

In an announcement Friday, Facebook said it has suspended the apps and accounts associated with Rankwave and is asking the court "to enforce the basic cooperation terms that Rankwave agreed to in exchange for the opportunity to operate apps on the platform."

"By filing the lawsuit, we are sending a message to developers that Facebook is serious about enforcing our policies, including requiring developers to cooperate with us during an investigation," Facebook's announcement said.

Rankwave's website seems to have been taken offline shortly after the lawsuit was filed. We asked Rankwave for a response to Facebook's lawsuit and will update this story if we hear back.

Facebook describes investigation

Facebook's lawsuit said the social media giant began investigating Rankwave "in or about June 2018," after Rankwave was acquired by a Korean entertainment company named CJ E&M. When the acquisition happened in May 2017, "the Facebook data associated with Rankwave's various apps received valuation of approximately 11 billion South Korean won (approximately $9,800,000)," Facebook said.

Facebook said it found that, since at least 2014, Rankwave violated Facebook policy 6.1 by "us[ing] Facebook Pages data associated with its apps for its own business purposes, which include providing consulting services to advertisers and marketing companies." Facebook said that Rankwave "has been unjustly enriched in the amount of $9,800,000 by violating Facebook's policies, including the Platform Policies and TOS [terms of service]."

Facebook sent Rankwave a written request for information in January 2019, asking for proof that Rankwave was complying with its contractual obligations.

"Facebook also sought to determine which specific Facebook data Rankwave used to sell advertising and marketing services, including whether any user data had been impacted," Facebook's lawsuit said.

Rankwave didn't respond within the two-week deadline, so Facebook sent a cease-and-desist letter in February. The letter told Rankwave that it violated Facebook policies by failing to provide proof of compliance with Facebook policies and terms of service.

Facebook demands deletion of user data

The cease-and-desist letter also demanded that Rankwave do the following:

Provide a full accounting of Facebook user data in its possession;

Identify all individuals, organizations, and governmental entities to which it had sold, or otherwise distributed, Facebook user data;

Provide a full record of the access logs and permissions it had granted third parties to access the data;

Delete and destroy all Facebook user data after returning it to Facebook;

Provide Facebook with full access to all storage and related devices so that Facebook could confirm deletion and destruction of the data through an audit.

Rankwave initially said it needed more time to respond, then "claimed that it had not violated Facebook's TOS or Platform Policies," Facebook said. But Rankwave failed to provide any proof that it hadn't violated the policies, and it ignored the audit request and other demands in the cease-and-desist letter, Facebook said.

"Rankwave further claimed that it had not had access to any of its Facebook apps since 2018. This statement was false, however, as Rankwave continued to use at least one of its B2B apps until at least April 2019," Facebook alleged.

Facebook said it gave Rankwave a deadline extension to March 6 but that Rankwave has still failed to comply with its requests.

Facebook's complaint says that Rankwave's misconduct "harmed Facebook's reputation, public trust, and goodwill." Facebook asked for financial damages and disgorgement of all value Rankwave unjustly received, but it also said that money alone won't be enough to remedy the harms caused by Rankwave.

The suit asks for an injunction that would prevent Rankwave from accessing the Facebook platform, require Rankwave to respond to Facebook's requests for proof of compliance (including a forensic data audit), and require Rankwave "to delete any and all Facebook data as appropriate after Rankwave complies with" the audit requirement.