It is easy to communicate with node.js app by socket. Using node.js to create a Net server (http://nodejs.org/api/net.html), and client use socket to connect to it. In my opinion it is easier to build a server with Node.js than C/C++ and has nice performance.
BTW, I think using node.js as server has gradually become a common solution. And My company have developed a mobile game with pomelo which is a node.js game framework.
For more infomation you can see this article http://www.toptal.com/nodejs/why-the-hell-would-i-use-node-js