The most recent example comes from the World Bank. They recently published their Mapping for Results site, which presents (on a map, of course) details of 1250 current World Bank-financed projects in over 16,000 locations in 79 countries. Each location has a marker that can be clicked to reveal more details of the project and its location.
For Tanzania, the map shows 40 financed activities in 524 locations:
|Mapping for Results - Tanzania map (click to enlarge)|