The use of authentic tasks is derived from social constructivist principles of locating learning in the context of reality. Authentic tasks can foster learning transfer because collaboration among students not only helps them learn the concepts under discussion, but also exemplifies how these concepts are used in real-world contexts. To achieve a challenging authentic task, students must interact--sharing their thoughts, relating their ideas to past experiences, collaborating with their peers, actively constructing their own meaning, and incorporating the diverse perspectives of others. Social constructivists believe learning can be enhanced through these types of interaction. According to the theoretical principles of social constructivism, well-designed and well-operated courses focused on authentic activities should meet the expectations of meaningful interaction that contribute to student growth and learning. This article presents two Web-based learning case studies on using authentic tasks. The instructors who designed and managed these two courses offer several suggestions for implementation of authentic tasks in online courses. The information presented here pulls from an analysis of the transcripts of the discussion board postings and chat room exchanges in the two courses and on in-depth interviews with the two Australian instructors and with seven students who participated in the courses. (Contains 1 table and 31 endnotes.)