[chrisdc]

I'm happy to share. I'll do a blog post on this down the line, but here's the outline....

Node.JS at the core. Redis and AWS SimpleDB for the Database. Major caching at all levels (frontend/backend). Response times of less than 50ms for most calls. Web Sockets(SocketIO) for real time communications.

The frontend is built entirely in AngularJS with a few jQuery integrations. We write all our CSS in LESS and compile it using Grunt.

We used PHP (LAMP) for our last major Project and I can say that for what we are trying to achieve, NodeJS is much much much faster(10x) and leaner(we manage the same traffic with 20% of the server resources used on our last project with PHP)