Considering how well a company like Netflix does, I think that Amazon is way behind the times on its recommendation engine.
It is 10000 films vs several million products. Plus if you are in to action films it isn't hard for an algorithm to recommend other action films but if you buy Final Fantasy X, toilet roll and massage oil all in one order then I am not sure what association the computer can really make.
Why do you have this need to label people? If someone from Scotland or Northern Ireland wants to self identify as British then you can just let them - you don't need to tell them how they are wrong just because you read a wikipedia entry on the etymology of the word.