Sean Parsons and Mark Baker from MindCandy discuss their use of Scala in services and tools. They chose Scala due to familiarity with the JVM, static types, and its large community. They used Scala to build backend services including for users, games, news and more. They also used Scala for tools like the REPL, scripts, a setup tool and Play-based websites. They found Scala good for expressing algorithms clearly and taking advantage of immutability and actors to scale. While learning Scala required learning new syntax and paradigms, they plan to continue using it for tools, scripts and services going forward.