The toolbar on the web mapping site allows you to do many of the basic operations you would carry out in GIS. These are from top left, top right etc.:
Toggle between legend and layers list. Switch overview location map on or off.
Zoom in to selected area. Zoom out X 2.
Zoom to extent of all layers. Zoom to active or selected layer.
Back to last extent. Pan by Hand
Identify the selected area on screen (Based on active layer selected!) Build a Query
Find a certain feature. Measure tool for on map distances, (either single line or polyline)
Select measuring units Buffer a line or, point or polygon to query between layers.
Select rectangle. Select by line or polygon.
Clear Selection. Print Map/Screen

The viewer controls the map image he or she sees by selecting which layers to make Visible (can be seen) and which to make Active (i.e can be queried or features identified). These are switched on or off in the aradio buttons opposite the layer names in the right-hand men

One of the most useful features is the ability to construct queries, based on attributes of the tables on which the maps are built e.g. querying all the characteristics of a selected rectangle, or highlighting on the map a given feature. Once selected these features can be "zoomed to" from the hyperlinks returned with the query.

http://spatial.dcenr.gov.ie/imf/imf.jsp?site=INFOMAR