This document outlines 10 lessons learned about test automation from eBay. It provides facts about eBay, including that it has 27770 employees worldwide and processes 2 billion page views and 75 billion database calls daily. The lessons recommend flipping the testing triangle to focus more on automation, ensuring everyone knows what is automated, using test aspects to guide automation, and treating automation as software development. It emphasizes the importance of maintainability, using the same language as developers, investing in test infrastructure, and that manual testing remains important alongside automation.