One of the unique features of ArcGIS Explorer is that you can easily set up your own Explorer home server, and can control everything from the startup banner, the default map, the appearance of the navigator, whether users can add new layers, save a map, add tasks, and much more. This allows you to customize Explorer for your target audience, or tune it for a specific workflow.
This is covered in the ArcGIS Server Help, since many users that implement this would also be using ArcGIS Server to publish their own maps and tasks. But a nice feature about this capability is that it doesn’t require ArcGIS Server, or any other ESRI software for that matter. All you need to do is edit two XML files – a configuration file and a skins file – and put them in your wwwroot directory as described in the Help. Then simply point Explorer to your home server instead of the default ESRI home server. These XML files are automatically read by Explorer from its designated home server at startup, and provide you the capabilities to control a wide variety of user options and the look and feel of the application.