This document discusses auto-scaling in the cloud and provides a case study on MediaHub, a media sharing application. It describes MediaHub's architecture, which uses various AWS services like EC2, RDS, S3, CloudFront, and Elastic Beanstalk. It then provides best practices for developing applications in the cloud, such as automating infrastructure, controlling permissions, automating configuration, and designing for redundancy and parallelism. The document concludes that the cloud is not suitable for all applications and that applications must be designed for cloud-scale to reduce costs.