Do I need ArcGIS Server to use ArcGIS Explorer?
ArcGIS Explorer is ready to use and connects directly to ArcGIS Online, which powers the default map, basemaps, and tools you use. Though you don’t need ArcGIS Server, you can extend the maps and capabilities of ArcGIS Explorer by authoring and publishing your own maps and layers via ArcGIS Server or by authoring geoprocessing tools, which can extend the ArcGIS Explorer capabilities via add-ins.
