The document summarizes eBay's Hadoop analytics platform called Athena: 1. Athena is eBay's large Hadoop cluster comprising over 500 nodes that was built in 2010 to power advanced analytics on complex data. 2. The platform runs the Hadoop ecosystem including HDFS, MapReduce, HBase, Pig and Hive for data access and processing. 3. Athena is used for applications like search relevance ranking, data mining and description extraction to enhance eBay's catalog and search capabilities.