https://www.reuters.com/article/us-facebook-results/facebooks-grim-forecast-privacy-push-will-erode-profits-for-years-idUSKBN1KF2U5

Facebook Inc's shares lost as much as a quarter of their value on Wednesday after executives said that profit margins would plummet for several years due to the costs of improving privacy safeguards and slowing usage in the biggest advertising markets.