This paper explores the search effectiveness of social tagging which allows the public to freely tag resources, denoted as keywords, with any words as well as to share personal opinions on those resources. Social tagging potentially helps users to organize, manage, and retrieve resources. Efficient retrieval can help users put more of their focus on studying the resources rather than the retrieval process. This study was an investigation into the relations between social tags and user queries. Our findings were summarized into 4 main points: (1) 85% of the surveyed users agreed that social tags assisted them in searching for resources; (2) Over 40% of user queries searches, found their resources via the matching of social tags; (3) Social tags matched over 70% of user queries; and (4) 14% of the social tags for a resource did not appear in the context of the resource. The experimental results demonstrated that social tags can improve users' efficiency in searching for resources. (Contains 1 table and 7 figures.)