YouTube doesn’t share exact user info. But, google ads platform does have the metrics and can show the Amazon seller statistics of interest when buying ad prints on YouTube videos. Like search terms and referral links click right after or before the video played.

This happens automatically and virtually without human intervention though. It’s just bots talking to bots talking to bots. It all happens in milliseconds after you click play. By the time your web browser has started loading the player, yt opened a bid for the ad spot, thousands of companies chose to bid on that video based on a myriad of parameters and statistics, a winner was chosen based on pledged money, then a video ad is loaded to the server ready to play.

GAds assigns every video several keywords, based on information from the uploader, then watches user behavior to assign meta tags. Videos are scanned, to search for curse words, nudity, copyright and other offending material automatically. I don’t think they scan for objects shown in the video to assign tags about the kind of product, but it’s not out of the realm of possibility.