Anyone can track you with $1,000 of online ads

For around $1,000, anyone can buy online ads that could allow them to track which apps you use, where you spend money, and your location, new research suggests. Privacy concerns have long swirled around how much information online advertising networks collect about people’s browsing, buying, and social media habits—typically to sell you something. But could someone use mobile advertising to learn where you go for coffee? Could a burglar establish a sham company and send ads to your phone to learn when you leave the house? Could a suspicious employer see if you’re using shopping apps on work time? The answer is yes, at least in theory.