[ristretto]

Credit card issuers have access to this information for years, right? I suppose there will be some relevant legislation somewhere. Google is bound to be doing this on a very large scale though and i m pretty sure these terms are already violating privacy laws in certain countries.

It is one thing to use the search data, because it involves just Google, so at least you know your private info is not spilled over. Using data from merchants is a whole different thing. Actually i m pretty sure many merchants will frown upon the fact that google knows what their customers are buying (thus potentially leading them to competitors and breaching buyer's trust).