This document discusses open data and lessons learned from open data initiatives. It outlines the triple objectives of open data as more transparent government, improved public services, and new economic and social value. It then provides several case studies that demonstrate significant returns on investment from open data, in areas such as transportation, healthcare, addressing, weather, and more. The document concludes by discussing lessons learned from open data projects, including the importance of leadership, managing expectations, incremental delivery, engagement, and focusing on high-value data.