The actor model is a novel approach to writing concurrent software. It is based on the concept of small computational units communicating through asynchronous message passing, thus allowing concurrency and scalability while negating a lot of the problems of concurrent programming.
The actor model has been gaining adoption with the Erlang language and the Akka framework for JVM languages. But up until now, the .NET landscape lacked a truly robust and production ready actor framework. This changed dramatically this year with the release of not one but two open-source actor frameworks for .NET - Akka.NET (a port of the JVM Akka), and Orleans by Microsoft.
Presented at the Gigya Meetup group, June 2015.