Facebook “allowed” Cambridge-Analytica to Hoover up a massive amount of psychometric data on US voters before the 2016 election (ins care quotes because they “allowed” it in the sense they prevented it by policy but did nothing significant to deter the data collection at scale).

I would argue that FB’s bigger wins have been in being the first app / website to get perhaps 50% of the world population using it, and also the Herculean effort it took to moderate that’s volume of content (whether or not you agree that moderation was the right choice or successful).