Building Applications with AWS Paul Duffy discusses how AWS provides a full spectrum of capabilities for building applications. It allows startups to build with no upfront costs and provides agility. AWS supports SMBs, enterprises, and has over 100,000 customers across 190 countries. It can host any type of application from simple to complex websites, as well as mobile apps, analytics platforms, and more. AWS provides automation, elastic scaling, high availability, low latency globally through services like S3 and DynamoDB. Examples discussed include clickstream analytics, backup/DR, Oracle applications, and even NASA's use of AWS for applications on Mars.