TLDR: Rails Live Streaming allows Rails to compete with Node.js in the streaming arena. Streaming requires application servers to support either multi-threaded or evented I/O. Most Ruby application servers are not up for the job. Phusion Passenger Enterprise 4.0 (a Ruby app server) is to become hybrid multi-processed, multi-threaded and evented. This allows seamless support for streaming, provides
![Why Rails 4 Live Streaming is a big deal](https://cdn-ak-scissors.b.st-hatena.com/image/square/f156afe3548426c44d531ff0b35e6829f54835d6/height=288;version=1;width=512/http%3A%2F%2Fblog.phusion.nl%2Fwp-content%2Fuploads%2F2012%2F08%2FPhusionRoadmapPreview1.png)