I would add Stackoverflow for a very significant amount of queries. In particular in the domain of web development extremely outdated answers are heavily outran

I would add Stackoverflow for a very significant amount of queries. In particular in the domain of web development extremely outdated answers are heavily outranking far better answers. It shows how domain/link age is a strong factor in ranking, which is also why w3schools ranks highly. That's bad, but I can somewhat sympathize with it as these sites are not really purposefully gaming SEO. It's rather Google's poor handling or relevancy and recenctness. That's an entirely different situation from scammers like pinterest. They clone content without permission and then rank higher than the original. They broadcast content to be open to search engines yet when you visit, it's behind a login. The behavior of duplicating content will normally tank your ranking. Faking content to not be behind a login where it really is behind a login, may get you fully delisted. But not pinterest, they seem to get a free pass for anything.