Students now have at their disposal a range of Web 2.0 authoring forms such as audio and video podcasting, blogging, social bookmarking, social networking, virtual world activities and wiki writing. Many university educators are interested in enabling students to demonstrate their learning by creating content in these forms. However, the design and conduct of assessment for such student-created content is not straightforward. Based upon a review of current literature and examples in the public domain, this paper identifies key challenges for academic assessment that arise from students' use of Web 2.0 authoring forms. We describe and analyse selected cases where academics have set assessable student Web 2.0 activities in a range of fields of study, noting especially the inter-relationship of learning objectives, assessment tasks and marking criteria. We make recommendations for practice, research and understanding to strengthen educational quality and academic integrity in the use of Web 2.0 authoring forms for assessable student learning. (Contains 1 table.)