We reviewed the theoretical base and international research on using Web 2.0 applications for learning through collaboration. We found evidence of effective uses of Web 2.0 applications such as blogs, wikis, collaborative concept mapping, VoiceThread, video sharing, microblogging, social networking, and social bookmarking that applied contemporary and foundational educational theory. We will share opportunities and challenges associated with learning through collaboration with Web 2.0 applications, and research directions and areas to explore for ECT researchers.