I learned that Esri is a 40-year old mapping company that has moved its products from the mainframe to client server to the desktop and now to the cloud. They focus on "where," and provide products and platforms centered around the theme of "geography as a service."
Esri's ArcGIS product (available in the AWS Marketplace) runs on EC2 and gives users the ability to create, edit, annotate, and share maps. For example, here are some of the maps that were created in the aftermath of Hurricane Sandy.
Jim told me that AWS and EC2 give them the ability to scale rapidly and to stand up dynamic maps as part of disaster recovery efforts.