Actors are very lightweight concurrent entities. They process messages asynchronously using an event-driven receive loop. Pattern matching against messages is a convenient way to express an actor's behavior. They raise the abstraction level and make it much easier to write, test, understand and maintain concurrent and/or distributed systems.
One of the improvements that came with Scala 2.10 is completely rewritten and improved pattern matching. In addition to fixing some performance issues (e.g.this exponential space bytecode bug), it fixes a few of the annoyances I’ve had with pattern matching in Scala and gives much more useful errors at compile time.
Apache Camel has been completely rewritten for Akka. Camel is an open-source framework based on known Enterprise Integration Patterns and it is great for integrating Akka systems with other external systems. The Akka Camel module provides an easy to use bridge between actors and Camel endpoints.