Happstack gets a new brand identity (Haskell Application Server Stack)

The (new?) front page does a good job of answering "Why should I be interested in Happstack?", but I'd like to be able to drill down to more detail. For example:

"Happstack's unique MACID distributed persistent data storage layer is based on the lessons learned and shared by high traffic sites such as Amazon, eBay, Facebook, and reddit."

That sounds like either a killer feature or an overengineered pipe dream. I'd love to be able to find some code examples, or an article explaining what exactly MACID learns from the challenges of scaling Facebook and how it helps. It would be great if that "hook paragraph" had links to such articles so I didn't have to Google and filter results for quality.