Amazon’s people who bought recommendation system, is a way to harness the hive mind/wisdom of the crowds through data.
So do any game portals/app stores use a similar system e.g. Players who played this also played/purchased.
Steam.
They have discovery queue that demonstrates you products based on what you played/bought, you can scroll front page down and see bunch of recomendations, and during checkout there’s “people also bought this” screen.
This mechanism is not perfect, however.
i always just expect all those are paid for lol
… preeeettttyyy suuure theyre paid for lol
( i have no idea really lol … buut they probably are 
)
on amazon, it seems like its usually the most expensive thing of the type