Crowdsourcing is the practice of obtaining needed services, ideas, or content by soliciting contributions from a large group of people, and especially from an online community, rather than from traditional employees or suppliers. Nowa- days, lots of people begain to post their ideas and viewpoints on SNS platforms such as Twitter, Facebook or Sina Weibo. Such information can be collected to identify what is users are good at. Analysising this data on SNS platform can help recognize which expert the user would be on question and answer systems. In a result, the system could provide more accurate people when a user ask a question.