Exploring GitHub Topics: Unveiling Their Content and Potential

N owadays, software service design is increasingly oriented toward addressing human needs, aiming to extract users' needs and behavioral patterns from open-source data. GitHub's massive open-source repositories have emerged as a crucial data source for software service researchers seeking to extract valuable insights and develop software services tailored for developers. Both GitHub and researchers are making efforts to help researchers and developers better utilize GitHub data. In 2017, GitHub launched “topics”, enabling developers to assign keywords to repositories. This feature fosters linkages between repositories, aiding in their discovery by other developers. For software development, topics offer two significant values. First, topics provide researchers with new insights to better mine GitHub data and provide enhanced support for developers. Second, developers utilizing topics to annotate their repositories may enhance their visibility and engagement within the community, potentially bolstering their repository's popularity. Despite the increasing number of topics, no research has systematically analyzed their content and potential value. Therefore, we conduct the first empirical study on topics, providing valuable conclusions for future researchers and developers. We conduct a case study encompassing 900 repositories to analyze the information explicitly presented in the topic content, and three experiments to verify whether topics have the potential to be used as repository features and user features in GitHub-related studies. Furthermore, we delve into the correlation between topics and repository popularity, by analyzing the number of stars repositories received. Our findings cover the composition of topic content, the potential value of topics for GitHub-related research, and the impact of topics on repository popularity.