Abstract. The Web is a vibrant environment for innovation in computer science, AI, and social interaction; these innovations come in such great number and speed that it is unlikely to follow them. This paper will focus on some emerging aspects on the web that are an opportunity and challenge for Case-based Reasoning, specifically the large amount of experiences that individual people share in the Web. The talk will try to characterize this experiences, these bits of practical knowledge that go from simple but practical facts to complex problem solving descriptions. Then, I'll focus on how CBR ideas could be brought to bear in sharing and reusing this experiential knowledge, and finally on the challenging issues that have to be addressed for that purpose.