Your shopping habits are uniquely identifiable

While obvious to say, use cash.

Patterns are uniquely generated in almost all types of information. What has been missing until the great rise of the World Wide Web is intent to monetize. Earlier companies sold you products like Microsoft Windows, Coca-Cola and Apple Macintoshes. Advertising paradigms like television advertising, radio, newspapers while really nice, had a "last-mile-connectivity" problem - you never really knew how you got your customer - through TV, radio? I do understand Nielsen and other ratings companies and some TV analytics historically try to ameliorate this, but the internet has been the greatest driving force in the last few years. Google and Facebook etc. and internet driven content engines have all traded eyeballs for content or products. As a result, the intent to improve advertising for the eyeballs (since presumably the eyeball count has a theoretical upper bound) has become the force du jour. Hence the ability to identify stuff was there, except for the machine learning part which has grown up from academia tremendously. It is just that now we have the intent to use all this to identify and collect patterns from all sorts of data. Whether that is good or bad or gray is another matter.

My role in the house is to buy the cat food and the hard liquor.

I imagine someone at the supermarket statistics centre studying my shopping habits and wondering how one family can survive on whisky and Friskies Chicken & tuna dinners.

It's not that uncommon - I had a meeting with wal-mart's data team once where they talked about how there are certain pairs of purchases that are highly correlated with male shoppers - beer and diapers was one I remembered.

I came in expecting something like an Amazon shopping history. I don't find it too surprising that in-person purchases can be tracked so readily - geographic information is a huge dimension to add to these data. It would be interesting to see how many data points are necessary to achieve similar accuracy just with a purchase history. Particularly interesting would be matching users across websites.