One of Explorer's distinguishing features is its ability to connect directly to a wide variety of Web service-based content and a wide variety of local data, both vector and raster, and integrate and manipulate them all in a single map. It's truly in a league of its own in this regard. Shown below is Explorer with:

• 2 ArcGIS Online layers
• 1 WMS layer
• 1 ArcIMS layer
• 2 2D ArcGIS Server layers (1 of them dynamically updated every 10 minutes)
• 1 3D ArcGIS Server layer
• 1 KML (from the USGS site)
• 1 KMZ (from the NOAA site)
• 1 Shapefile
• 1 Result (a collection of points imported from GPS coordinates in a textfile)
• 1 BSQ raster image (from the EROS Data Center)

And we could add even more.

Several of the layers have been made partially transparent so they can be overlayed, and several have scale dependencies. The underlying data sources for the Web-based content include everything from enterprise ArcSDE geodatabases, file and workgroup geodatabases, and local sources that include shapefiles, rasters, and points added from textfiles containing GPS coordinates.