EFF: “We’ve been seeing a range of reports about Facebook partnering up with marketing company Datalogix to assess whether users go to stores in the physical world and buy the products they saw in Facebook advertisements. A lot of the reports aren’t getting into the nitty gritty of what data is actually shared between Facebook and Datalogix, so the goal of this blog post is to dive into the details. We’re glad to see that Facebook is taking a number of steps to avoid sharing sensitive data with Datalogix, but users who are uncomfortable with the program should opt out (directions). Hopefully, reporting on this issue will make more people aware of how our shopping data is being used for a lot more than offering us discounts on tomato soup. Datalogix is an advertising metrics company that describes its data set as including “almost every U.S. household and more than $1 trillion in consumer transactions.” It specifically relies on loyalty card data – cards anyone can get by filling out a form at a participating grocery store.”