If you’ve used the Internet for longer than the iPhone has been around, you’re probably familiar with cookies, those little packets of personal data that help load websites you frequent and tell the websites’ owners who you are and what you’re up to — information coveted by advertisers. Since Netscape programmer Lou Montulli invented the cookie 20 years ago, it’s become a cornerstone of the online display and search advertising business, valued at $35 billion a year in the U.S. Montulli says he designed the cookie to make the Web more efficient and calls its use as a tracking device an “unintended consequence.”The good news for those who don’t like to be watched online is that cookies haven’t changed much in two decades, enough time to develop ways to stop them from gathering all that data. Browser security settings can limit or block cookies used by advertisers. Twelve percent of Firefox users around the world have opted into Mozilla’s do-not-track program, and Microsoft’s Internet Explorer and Apple’s Safari now block many cookies by default. Most mobile devices, including the iPhone, don’t allow use of cookies in apps.
www.businessweek.com/articles/2014-08-21/facebook-google-go-beyond-cookies-to-reap-data-for-advertisers