This document discusses how to auto scale .NET applications in Amazon Web Services. It covers key concepts like scalability versus auto scaling, using a load balancer and solving session issues for web applications, and monitoring applications to enable auto scaling. The document provides an example of scaling an application from 2 web servers and 3 application servers in 2012 to 3 SQL servers and more elastic resources like SQS and ElastiCache by 2015. It also discusses best practices for auto scaling like using out-of-process sessions, log collection, and setting CloudWatch alarms to trigger auto scaling rules.