This document discusses how big data analytics is used in advertising. It defines big data as large amounts of organized or unorganized data, measured in petabytes which equals 1000 terabytes or 1000 gigabytes. Big data analytics involves analyzing raw data to make sense of it using tools like Hadoop, MapReduce, Spark and TiMR. The document explains how big data helps target customers with relevant ads, potentially increasing sales. It provides examples of major companies that have benefited from big data analytics through increased decision making, traffic, clicks and revenues. In conclusion, the document argues big data analytics will become necessary for companies both large and small to serve relevant ads and increase profits.