Cambridge Analytica was a counsulting company that infamously used large amounts of data gathered from Facebook to help target political advertising. The extent of this was uncovered in 2018 including its use in the 2016 Trump presidential campaign. The use was deemed to have violated privacy and various data protection laws and Facebook was subsequently fined in both the UK and USA.
Used on Chap. 20: pages 488, 489, 492, 502, 505; Chap. 21: page 514
Wikipedia: