Facebook says it will begin informing users as to whether their personal data may have been wrongly shared with a British research company. Beginning Monday, Facebook said users who may have had private data shared with Cambridge Analytica will receive a message about it in their News Feed. The company believes up to 87 million people might be have been affected. Facebook says most of them are in the United States. It says there were about a million users affected each in the Philippines, Indonesia and Britain. Facebook says the information Cambridge Analytica got was first collected by a researcher at Cambridge University. The researcher gathered the data in 2013 through an app that asked users a series of questions for what was described as a personality test. The users used Facebook to sign into the app. Facebook says information may have also been shared on people who did not sign into the app, if they were Facebook friends with users who did.