The document outlines lessons learned from A/B testing best practices presented by Dan Siroker, Co-Founder and CEO of Optimizely. The key lessons are: 1) Define quantifiable success metrics, 2) Less is more - reduce choices, 3) Words matter and focus on the call to action, 4) Seek the global maximum, 5) Fail fast, and 6) Start testing today. Examples are provided of A/B tests run on buttons, media, and donations that demonstrate these lessons. The future of optimization is moving from testing for the average user to personalized testing for user segments and individuals.