ArcReader and ArcGIS Explorer are two free viewers offered by ESRI, but ArcReader requires that maps be published using ArcPublisher, a fairly costly extension. Can anyone familiar with both ArcReader and ArcGIS Explorer outline some of the key differences in ArcReader and ArcGIS Explorer -- in particular some functionality in ArcReader that makes purchase of ArcPublisher worthwhile, when ArcGIS Explorer is free.
