This document discusses big data use cases that use Amazon Elastic MapReduce (EMR) and Hadoop on the cloud. It provides examples of companies like a big box retailer, Etsy, Yelp, and Foursquare using EMR to perform clickstream analysis, recommendations, process large amounts of log data, and analyze user check-in patterns from terabytes of data. EMR allows these companies to easily run Hadoop jobs and experiments on large, scalable cloud clusters and lower the costs of operating distributed data systems.