Given that they went with Node.js and talked about scalability, I assume they wanted the async nature of Node.js to maintain a large number of connections. I'm surprised they didn't try out Netty since they are a Java shop. The last time I investigated Node.js for async connection support in a project, the benchmarks I did showed that Netty could scale substantially better than Node.js in term of number of connections, memory usage, thread utilization, and raw performance on the same hardware. That was a year and half ago. Things might be different now, but I doubt some of fundamentals have changed much.

Anyway, it's good to try out new things. Kudos to them for doing something out of their mold.