This document discusses how major social media networks like Facebook, Twitter, LinkedIn, Pinterest, and Instagram utilize big data and Hadoop technologies. It provides examples of how each network uses Hadoop for tasks like storing user data, performing analytics, and generating personalized recommendations at massive scales as their user bases and data volumes grow enormously. The document also briefly outlines SkillSpeed's Hadoop training course, which covers topics like HDFS, MapReduce, Pig, Hive, HBase and more to prepare students for jobs working with big data.