We have toured a lot of technologies for this mashup. Some of these are pretty cutting-edge, but necessary to incorporate a relatively new specification. Not surprisingly, your data sources are not always going to be from web APIs. Staying flexible and searching for new technologies to use in your applications is important. At last, we have the knowledge to start building the application.
The database is a good place to begin. Recall from our sequence diagram that a visitor directly and indirectly interacts with several different components of our application at any one time. Many of the components rely on the Google Map to be built first, but the map relies on the database as a source for marker locations.