(Image source: adweek.com) After the closing bell yesterday, Facebook Inc (NASDAQ:FB) reported better than expected fourth quarter earnings. The social media giant had profits of 31 cents a share, excluding certain items on total revenues of $2.59 billion. Profits exceed estimates by four cents. Mobile advertising drove overall revenues to increase 63 percent in the quarter. Advertising revenue alone came at $2.34 billion. Mobile ad revenue generated about 53 percent of total advertising revenue. Facebook’s shift towards mobile is clearly working. In addition, daily mobile users rose 49 percent. The site now boasts about 556 million mobile users.