Whats’s this Node.js I hear you say ??? See Felix Geisendörfer’s post Understanding node.js for some background explanation. Manuel Kiessling’s Node.js tutorial is also pretty good if you are coming from a more traditional server side programming background (like me).
Node.js is pretty good at low response/high concurrency tasks. You can download a VM for your server, however it’s now being supported by a number of the PAAS providers such as Heroku, Cloudfoundry, dotCloud, Nodejitsu , Nodester …. We’re expecting more to follow suit shortly.