Recent past has witnessed a proliferation of online maps and resources that, with their machine- accessible web services, enable the tech-savvy to mix-and-match these services to create web applications of novel utility. Many of these applications, so-called mash-ups, again are online resources that attract large populations of users and receive voluminous user feedback. If the Web is to be seen as the platform for building the next generation culture atlas, who are the contributors and what motivate them? In this presentation we contemplate these questions from the perspective of user participation and collaboration. We will identify the key issues and propose ways to address them. We have been building a prototype system called Web3P (“A Web of Place, People, and Participation”) to experiment with various design elements and implementation techniques to facilitate collaborative geospatial mapping. We will present our experience from using the prototype to map the geographic and cultural landscape of Orchid Island (Lanyu), the home to the Tao aborigines of Taiwan.