Comment by webjprgm

E.g. node.js + socket.io. The event-driven concurrency model makes it easier to write servers without worrying about race conditions and thread locks while also having less overhead from a heavy thread implementation. For some applications this has been quite good. The downside is that it can be a bit tricky to scale node.js larger but it's not too hard to run multiple processes or do other load balancing. It's not good for all applications, but very good for some.