Earlier this month, Facebook announced they would be reducing the number of their ad units from 27 to less than half of that. Part of that streamlining method is taking out this July the Sponsored Results. You have been seeing these with brands, groups, and searches since August 2012.
Facebook decided to take it out after noticing that marketers used Sponsored Results and mobile app install ads quite similarly. Businesses will still be able to use the latter method along with post link ads.