This document summarizes topics related to big data including: the size of big data in petabytes and exabytes; technologies like Hadoop and MapReduce that can handle large, unstructured data; and examples of big data systems like airline reservation predictions, Google Translate, Netflix movie recommendations, and Amazon book recommendations. These systems analyze huge amounts of past user data to make personalized predictions and recommendations. Technologies like MapReduce allow parallel processing of big data across many servers to achieve scalability that is not possible with traditional databases and SQL queries.