Today I saw this post, Introducing the XMPP application server: The Twitter example. It's a very cool app server for XMPP messaging. It scales across machines when you add hardware. The example app it shows is based on the Twitter model. So if you want to write a scalable social app with Twitter-esque messaging, use the API.
What does this mean? One of Erlang's strongest points is it's ability to scale across CPU cores and machines with a mini