Facebook’s efforts in 2013 to simplify and prove the effectiveness of its ad products paved the way for future growth in spending. And as a mobile platform, Facebook has delivered scale and efficiency and will continue to pull mobile dollars in 2014. Twitter, which went public this month, will continue its push for brand dollars by partnering with TV networks. Its planned acquisition of mobile ad technology company MoPub will help improve Twitter’s self-serve ad platform. eMarketer estimates that next year, 88% of US marketers will use social media for marketing purposes, up from 87% in 2013. Though not all of these companies will buy paid advertising, they represent a base from which the social media companies can grow their ad business. Get the full story at eMarketer