Personally, in production I've used it for basic web apps, WebSockets and background workers that do the heavy lifting for a web application written in another

Personally, in production I've used it for basic web apps, WebSockets and background workers that do the heavy lifting for a web application written in another language such as Ruby. I've also talked to several others that are using Elixir for mobile game and Internet of Things back-ends. Now that I'm more comfortable with the language I'm looking to use it for something more ambitious, such as a messaging layer that's specific to a cluster of application's needs.