The tagging technique has been widely applied in existing Web 2.0 systems, where users label resources with tags for effective classification and efficient retrieval of resources. Location-aware geographical tags (geo-tags) are required if users want to mark location-sensitive resources to digital maps. Large volumes of different kinds of user-created tags pose challenges to the effective organization of community resources using tags. Issues such as guaranteeing the quality of tags and supporting various tag-based queries emerge. In this demo, we present MarcoPolo, a Web 2.0 community system that allows users to define the hierarchical textual geo-tags and mark resources to a map using geo-tags. Statistical and feedback mechanisms are applied to guarantee the quality of tags (including geo-tags). The MarcoPolo system provides two effective interfaces for users to browse and search resources: one is the keyword-based interface and the other is the map-based interface.