Youtube stops the retargeting of video viewers for display campaigns
Effective Sep 24th, Youtube has disabled the opportunity to build audiences based on exposure in display campaigns. Note that this does not apply to video campaigns.
As a solution display campaigns might be retargeted based on organic sources (such as clicks on brand website) or even on not Trueview video ads, for instance planned in the open exchange system or via Teads. Of course, this will not provide brands with the same reach levels as Youtube does.