Social　media　has　become　a　part　of　our　daily　life　and　we　use　it　for　many　reasons.　One　of　its　uses　is　to　get　our　questions　answered.　Given　a　multitude　of　social　media　sites,　however,　one　immediate　challenge　is　to　pick　the　most　relevant　site　for　a　question.　This　is　a　challenging　problem　because　(1)　questions　are　usually　short,　and　(2)　social　media　sites　evolve.　In　this　work,　we　propose　to　utilize　topic　specialization　to　find　the　most　relevant　social　media　site　for　a　given　question.　In　particular,　semantic　knowledge　is　considered　for　topic　specialization　as　it　can　not　only　make　a　question　more　specific,　but　also　dynamically　represent　the　content　of　social　sites,　which　relates　a　given　question　to　a　social　media　site.　Thus,　we　propose　to　rank　social　media　sites　based　on　combined　search　engine　query　results.　Our　algorithm　yields　compelling　results　for　providing　a　meaningful　and　consistent　site　recommendation.　This　work　helps　further　understand　the　innate　characteristics　of　major　social　media　platforms　for　the　design　of　social　Q&A　systems.