Or to update Feuerbach to the 21st century, you are what you spend, at least when it comes to evaluating your creditworthiness. The FTC claims that credit card companies are jacking up rates on consumers who use credit cards for marriage counseling or massage parlors. (But I understand that credit card companies no longer are accepting charges from medical marijuana clinics, which, bummer.) So far, squinty-eyed meanies at the card issuing banks are relying only on rough impressions based on which merchants you frequent, but a movement is afoot to get a finer-grained picture by analyzing the SKU codes for the individual products you purchase.
I have only a rudimentary sense of privacy in most areas of my life. I honestly don't care who knows what I buy, and can only be amused by attempts to understand me on that basis. If anything I suffer from a sense of being unknown, inaccessible. I'm exactly the kind of customer a merchant should try to charm by offering a product whose choice was intelligently informed by real information about my preferences; I would be far from offended.
I admit to a little curiosity about whether my spending patterns portray me as a potential deadbeat, but I figure that, with a 35-year credit history of actually paying my bills, any other information the card issuer gets is gravy. They must think I'm the Holy Grail of customers. When they cut off my credit, we'll know the entire financial industry has melted down.