Wall Street Journal: Twitter is set to take Yahoo’s place as the third-largest seller of online display advertising in the U.S., according to eMarketer. The social media site is expected to claim 5% of the U.S. display ad market this year, the online ad researcher said. Twitter still trails Facebook, with 25.5% of the market; and Google, with a 13% share. Yahoo, the third-largest display ad seller for the past four years, will fall to fourth as its share slips to 4.6%, eMarketer said.