I’ve set up something that looks like a website (for now only from very large distance): vyos.net.
It’s running MediaWiki, for two reasons, one rational and one historical. The rational reason is that MediaWiki is just a good handy CMS if you want indefinite number of loosely structured interlinked pages. It’s not perfect, but categories and namespaces are excellent tools to structure the pages in a flexible and convenient way, and built-in revision control is an awesome feature.
The historical reason is that the original vyatta.org website was a wiki (look at the Internet archive for prooflinks). It was running TWiki though, which lacks many features of MediaWiki.
Account registration is open, so anyone can add relevant information. Some pages like maintainer announces and download pages will be protected with edit rights management or flagged revisions, but in general everyone is free to edit. Design documents and related discussions will be in that wiki too.
There is no content yet, but there is some stuff at the Unofficial Vyatta Wiki that is worth moving there, especially the API reference pages. If anyone has time for it, feel free to do that.