Also see YouTube’s FTC settlement won’t end its problems with regulators | The Verge
"The FTC’s complaint alleges that YouTube did not properly notify parents and get their consent before collecting and using their children’s personal information. Specifically, YouTube collected “persistent identifiers” – such as cookies that are used to track viewers over time and across websites – for advertising to children. For example, a toy company with a YouTube channel could set its account so that a child who visited its channel received ads for the company’s toys when the child visited another website. Such use of persistent identifiers to track children on child-directed websites without parental consent violates COPPA.YouTube pays big for tracking kids | FTC
Besides paying $34 million to the State of New York and a record-setting $136 million COPPA penalty – which goes to the U.S. Treasury – YouTube must create a system for the channels on its platform to identify their child-directed content. Once the order has been implemented, viewers of that content will no longer be tracked for advertising purposes. The settlement also requires YouTube to provide COPPA training to employees responsible for managing YouTube channels. And YouTube must comply with the rest of COPPA’s requirements."