The document discusses Apache Hadoop, an open-source software framework for distributed storage and processing of large datasets across clusters of computers. It provides an overview of Hadoop core projects including HDFS, MapReduce, and related projects like Pig, Hive, HBase and Zookeeper. The document also references presentations and articles about Hadoop use cases at Yahoo and the evolution of the Hadoop ecosystem with higher-level tools and interfaces for programming, querying, and managing distributed Hadoop applications and data.