The AOL Mail Team will discuss our implementation of HBase for two large scale applications: an anti-abuse mechanism and a user-visible API. We will provide an overview of how and why HBase and Hadoop were incorporated into the massive and diverse technology stack that is the nearly 20-year-old AOL Mail system and the history of how we took our HBase/Hadoop apps through our traditional process of design, to development, through QA, and into production. We will explain how our practical approach to HBase has evolved over time, and we will discuss our lessons learned and some of our techniques and tools developed via our iterative dev/qa and operational processes. We will explain the pain-points we have experienced with erratic usage and edge-cases, and how we address problems when we run across them.