ArcGIS Online provides an easy way for GIS users to find and share useful content and resources, including maps, layers, and tools. These include a wide variety of specific file types unique to ESRI products, and you can view a complete list of supported content in the ArcGIS Online Help.
There's lots of content from ESRI and other users that you'll find on ArcGIS Online, but not all can be used directly in ArcGIS Explorer. For example, an ArcMap map document (MXD) can only be opened in ArcMap, and can't be used in ArcGIS Explorer. GIS users will know and understand these differences, but for beginning ArcGIS Explorer users it may be a challenge to explore (no pun intended) all of what can be found on ArcGIS Online.
To make things simple we've established two ArcGIS Explorer groups that offer an organized subset of what's shared by ESRI on ArcGIS Online and that represent a core set of useful maps, layers, and tools for ArcGIS Explorer users. Here's how you can find those groups.
First, go to the ArcGIS Online home site.
You'll see Search featured on the page, and you can enter keywords to find shared content that matches them. But we want to find the ArcGIS Explorer groups. So click the pulldown to the left of the input box and choose Search for Groups and enter AGX orArcGIS Explorer:
The results returned will include the two ArcGIS Explorer groups established by the Explorer team; the ArcGIS Explorer group and the ArcGIS Explorer Labs group.
The ArcGIS Explorer group includes a collection of ready-to-use maps and layers. Most of these are ArcGIS Explorer map content files (NMC files) and can be opened directly in ArcGIS Explorer.
Click the Contents tab to see what's available.
The ArcGIS Explorer Labs group is a place where you can find a wide variety of add-ins (EAZ files) that extend Explorer's capabilities. These are created by members of the ArcGIS Explorer team, and may represent capabilities that find their way into the core product. Then again, maybe not.
Though unsupported, these add-ins are fun, interesting, and useful, so check them out. Click the Contents tab to view them.
We'll cover how you can use what you find on these groups in upcoming blog posts.
Read more: http://blogs.esri.com/Info/blogs/arcgisexplorerblog/archive/2009/09/15/arcgis-explorer-groups-on-arcgis-online.aspx