With the rising unemployment rate, public libraries in the United States have been paying attention to providing career information services; users of the public libraries also appreciate these services. Social software facilitates the flow of information among individuals. With the increasing numbers of social software users, it is important for libraries to provide their services through a variety of ways, including through social software. This article first introduces the scope and features of social software, then gives an overview of general social-software applications in U.S. public libraries, and finally analyzes how social software is implemented for career information services. Suggestions for implementing social software for career information services in public libraries in Taiwan are also provided.