Purpose: This paper aims to provide an overview of the published literature and current use of social software by libraries primarily in the UK and USA. Design/methodology/approach: The paper's approach is a literature review and desk research. Findings: Libraries are experimenting considerably in this area and many Web 2.0 applications have been developed by libraries and librarians over the past few years. These tools offer the potential to enhance library services. Research limitations/implications: The area is one of rapid change, so the findings will date quickly. Practical implications: An overview of which technologies are being used most widely and might offer the most potential for library staff considering experimenting in this area. Originality/value of paper: Web 2.0 is an area with which many library staff need to become familiar quickly. This paper provides a useful overview of the topic. (Contains 1 figure.)