A dashboard is a collection of summary reports that are presented in
table or chart format. All the elements in the dashboard are tied to
common parameters and respond in a synchronous fashion to any
parameter changes. Each table or chart, further can provide drill into
detail report options. A dashboard can be designed using various
techniques. Excel Dashboard refers to building a dashboard right into
your excel spreadsheet or using the Excel data with a dedicated
dashboard software.
Hope this explains the basic overview
Nilesh
http://www.exceldashboard.org