Get ready to find out if your Facebook data has been swept up in the Cambridge Analytica scandal. Starting today, the 87 million users who might have had their data shared with Cambridge Analytica will get a detailed message on their news feeds. Facebook says most of the affected users – more than 70 million – are in the U.S., though there are more than a million each in the Philippines, Indonesia and the U.K.

In addition, all 2.2 billion Facebook users will receive a notice titled “Protecting Your Information” with a link to see which apps they use and what information they have shared with those apps. If they want, they may shut off apps individually or turn off third-party access to their apps completely.

Reeling from its worst privacy crisis in history – allegations that this Trump-affiliated data mining firm may have used ill-gotten user data to try to influence elections – Facebook is in full damage-control mode. CEO Mark Zuckerberg acknowledged that he made a “huge mistake” in failing to take a broad enough view of what Facebook’s responsibility is in the world. He’s set to testify before Congress next week.