Not entirely benign, but understandable: above all else, Amazon wants to know exactly what search results Google shows you for particular queries, so they can b

Not entirely benign, but understandable: above all else, Amazon wants to know exactly what search results Google shows you for particular queries, so they can better understand Google's ranking policies. They can't otherwise scrape search results as you, and getting the info as an anonymous user isn't nearly as valuable. So they need you, via an extension or toolbar, to (perhaps inadvertently) opt-in to letting them collect the data 'over your shoulder'.