Actually, it's not missing. From the article: The Journal’s ad revenue wasn’t affected by its recent drop in Google traffic because social media visits grew 34

Actually, it's not missing. From the article: The Journal’s ad revenue wasn’t affected by its recent drop in Google traffic because social media visits grew 34 percent in that time, keeping overall web traffic flat, Watford said. The Journal lets readers get some articles for free via social media like Twitter and Facebook, which the paper views as a marketing tool.