This document provides a summary of a presentation on Decision Model and Notation (DMN) and lessons learned from submissions to the UServ Product Derby decision modeling challenge. Key points include: - Submissions used different decision table formats and approaches to decision structure, showing a lack of interoperability between tools. DMN aims to standardize these. - Decision requirements diagrams were rarely used, with all logic encoded in business knowledge models. DMN separates requirements from logic. - Having a standardized business glossary and interchange format would improve tool interoperability. The presenters suggest further refinements to DMN to improve usability.