Structured community portals extract and integrate information from raw Web pages to present a unified view of entities and relationships in the community. In this paper we argue that to build such portals, a top-down, compositional, and incremental approach is a good way to proceed. Compared to current approaches that employ complex monolithic techniques, this approach is easier to develop, understand, debug, and optimize. In this approach, we first select a small set of important community sources. Next, we compose plans that extract and integrate data from these sources, using a set of extraction/integration operators. Executing these plans yields an initial structured portal. We then incrementally expand this portal by monitoring the evolution of current data sources, to detect and add new data sources. We describe our initial solutions to the above steps, and a case study of employing these solutions to build DBLife, a portal for the database community. We found that DBLife cou...