“By buying or licensing data or scraping public records, third-party data companies can assemble thousands of attributes each for billions of people… These days, if you use a smartphone or a credit card, it’s not difficult for a company to determine if you’ve just gone through a break-up, if you’re pregnant or trying to lose weight, whether you’re an extrovert, what medicine you take, where you’ve been, and even how you swipe and tap on your smartphone.
All that information can be used to create profiles of you—think of them as virtual, possibly erroneous versions of you—that can be used to target you with ads, classify the riskiness of your lifestyle, or help determine your eligibility for a job. Like the companies themselves, the risks can be hard to see. Apart from the dangers of merely collecting and storing all that data, detailed (and often erroneous) consumer profiles can lead to race or income-based discrimination, in a high-tech version of redlining.)”