Unless you use cash, there's probably an electronic record somewhere of every purchase you make. There may even be multiple copies of that record if your transactions are sold to data miners.
Data mining companies sort through piles of information, linking different sources together. They may use your Facebook activity, financial transactions, and more to make a rough sketch of who you are and what you like. This makes it easier for marketers to show products and services you're likely to buy.
As it gets easier to make electronic payments - with credit cards, debit cards, and mobile phones - data miners have more information to work with. You have to decide whether or not you're comfortable with this. It's not all sinister: most men probably don't care about ads for women's shoes, but they might enjoy learning about other products.
It's possible that you'll be penalized. During the financial crisis, some credit card users found out that their credit lines were cut because of where they shopped. If you make electronic payments, consider what might happen. Last weekend's Marketplace Money reviews how the process works.
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