Big data analytics has shown that the conventional wisdom about display ad clicks being worthless was incorrect. It revealed that people who click on ads (clickers) actually buy 3 times more frequently than non-clickers, and half of all clicks and sales come from just 20% of users. Real-time big data is now being used to serve highly targeted display ads to the right users at the right time with the right message, making the ads actually worth clicking on and representing a $20 billion opportunity for the display advertising industry.