This document summarizes Yoni Goldberg's talk on Gilt's transition from a monolithic Ruby on Rails application to a distributed system of over 450 Scala microservices. Some of the key challenges they faced included scaling issues as traffic grew, difficulties deploying and testing changes across many interdependent services, and a lack of clear ownership over parts of the codebase. Gilt addressed these by moving to the JVM, embracing microservice architecture, using Docker for development environments, implementing automated testing and deployment tools, and emphasizing clear ownership of individual services.