A statis dashboard is the one where we set an individual as the running user and who ever views the dashboard can see the data in the running user's perspective. In short the running user determines if it is a static or dynamic dashboard.
You can review the below article for more information between a static and dynamic dashboard
You can review the below article for more information between a static and dynamic dashboard
https://help.salesforce.com/HTViewHelpDoc?id=dashboards_dynamic_overview.htm&language=en_US