Twitter to Surpass Yahoo in U.S. Display Ad Revenue
blogs.wsj.com
blogs.wsj.com
Also, what this article doesn't mention is that display ads are only ~12% of Yahoo's revenue. I'm guessing they are a more meaningful part of Twitter's revenue. Not really an apples-to-apples comparison.
Reference for stat above: http://www.forbes.com/sites/greatspeculations/2014/07/16/yah...