Something you should keep in mind is that companies like Amazon are all well aware of the anecdote about Target and teenage pregnancies. And the lesson they l

Something you should keep in mind is that companies like Amazon are all well aware of the anecdote about Target and teenage pregnancies. And the lesson they learned from that story is they should conceal from the user the full extent of what they know about that user, to avoid creeping people out. If you receive 10 product recommendations, perhaps only one of them is actually targeted with a very high degree of confidence and the other 9 are basically noise added to deliberately deceive you, to lead you to believe Amazon knows less about you than they really do.