Personalize
A mapping application can use one or more content sources. Each content item corresponds to a service, such as an ArcGIS Server service or ArcIMS service. Each source contains one or more map layers. A map layer is a type of data shown on the map, such as roads, cities or a satellite image.
Users can view the list of the contents of the map, turn on and off layers, and examine the symbols for layers.
To examine the map contents:
. 
next to a content item to display the layers
within it.
next to the name, you can expand the layer
to display a legend for the layer. The legend
may display a single symbol or multiple symbols
for the layer.