Comment by probably_wrong

This has been my search engine quality test for quite some time.

A good search engine will show you pirate websites because they have a comprehensive index. A great search engine will put them at the top of the list ahead of the fake results.

A great search engine that endures long enough attracts the type of attention that forces them to delist those results. Once you can no longer find that type of results you know it's time to look somewhere else.