This document discusses various technologies related to mapping and geospatial data on the web. It provides 4 examples of different mapping platforms and technologies that combine web services, APIs, databases, and open source software to deliver maps and geospatial data through web applications. The examples showcase how ArcGIS Server, Amazon EC2, Microsoft Virtual Earth, and Google Earth can be used along with technologies like JavaScript, REST APIs, and spatial databases to create map mashups and geospatially enabled web applications and services.