This paper describes recent developments and trends of digital reference services. A brief overview of selected research on issues surrounding digital reference service is provided. It also discusses how technological developments in libraries have led to the emergence of new service paradigms. This paper briefly reviews reference and information services provided by libraries, those from publishers, those provided by experts, and those where users need to conduct a search and find information through the web. The current trend shows that the cooperative model is increasingly popular. Some projects on collaborative digital reference services(CDRS) are introduced. Librarians will need to continue analyzing the need for cooperative work in the reference service in a digital environment.