Some companies record — and then resell — your screen names, web site addresses, interests, hometown and professional history, and how many friends or followers you have, according to a report released this week. Some companies also collect and analyze information about users’ “tweets, posts, comments, likes, shares, and recommendations.”
If you’re a registered voter and surf the web, one of the sites you visit has almost certainly placed a tiny piece of data on your computer flagging your political preferences. That piece of data, called a cookie, marks you as a Democrat or Republican, when you last voted, and what contributions you’ve made. It also can include factors like your estimated income, what you do for a living, and what you’ve bought at the local mall.