The document provides an overview and quick reference guide to big data concepts including Hadoop, MapReduce, HDFS, YARN, Spark, Storm, Hive, Pig, HBase and NoSQL databases. It discusses the evolution of Hadoop from versions 1 to 2, and new frameworks like Tez and YARN that allow different types of processing beyond MapReduce. The document also summarizes common big data challenges around skills, integration and analytics.