In November 2006, ESRI began rolling out ArcGIS Explorer. It was initially made available to ArcGIS Server users who were current on maintenance, followed by ESRI Developer Network (EDN) subscribers and ArcGIS Desktop users. ArcGIS Explorer will soon be made available to the general public.
ArcGIS Explorer is a lightweight desktop client for ArcGIS Server, providing a way for users to publish ArcGIS Server capabilities within their organizations or to anyone on the Web. ArcGIS Explorer is freely distributable and does not require any other ESRI software.