https://techcrunch.com/2021/02/18/facebook-knew-for-years-ad-reach-estimates-were-based-on-wrong-data-but-blocked-fixes-over-revenue-impact-per-court-filing/ > Some more internal emails Facebook really doesn’t want you to see: Turns out in 2017 COO Sheryl Sandberg had already known for years there were problems with a free ad planning tool the company offers to marketeers to display estimates of how many people campaigns running on its platform may reach, per newly unsealed court documents. > The filing also reveals that a Facebook product manager for the ‘potential reach’ tool warned the company was making revenue it “should never have” off of “wrong data”.