Ben Christensen explains how Netflix manages to stay online even with millions of users, the Hystrix fault tolerance library, how Netflix discovered reactive programming and why it ported Rx to Java.
David Nolen explains the ideas behind logic and constraint programming, how they're used in his Clojure core.logic library, Prolog, the features in the Oz language and Mozart/Oz, and much more.
Sadek talks about the origins of Playframework, motivations behind 2.0 rewrite and Scala integration. He explains how important is it to have appropriate architecture and programming model while dealing with Realtime. He then reveals some features of the newly released 2.1 version.
Jeff talks about the powerful features that come with Grails 2 and how it can be used as a rapid application development framework. He also compares it with Rails and Django and explains how it can be combined with other components from the Spring portfolio.
Stuart Williams explains vert.x: basic idea and architecture, how it uses Java's NIO and async APIs, how it allows using various JVM languages (Groovy, JRuby, Scala, etc), the EventBus and much more.
Rich Hickey explains the basics of Datomic, its approach to transactions and query, Datalog, CAP, ACID and BASE, and much more.
Bob Lee explains the popularity of Java, future language features like Lambdas, DI with Guice vs. the Dagger framework, the role of Java vs. Ruby at Square, hiring at Square, security and much more.
Debasish Ghosh talks about the advantages of functional programming and how its abstractions help to reason about code, Monads, DSLs, NoSQL and MongoDB, and much more.
Ken Little talks about scaling Tumblr to keep up with their blogging users: scaling the data model, sharding, their PHP frontend and the Scala backend, and much more.
Rich Hickey explains how immutability enables Datomic's features and facilitates programming (not just in functional languages). Also: Datomic and other NoSQL stores, Clojure Reducers and much more.