As was explained in this thread, and as we've so clearly seen at vBulletin.org, a forum of random threads is not acceptable for documenting a product in active development.
The information quickly gets stale and out of date. There's no way to maintain the information if the author of a thread moves on to other projects. And none of the information is linked together in any meaningful way. Each guide ends up like its own island with half the useful information down on page 7 in the comments.
It seems like XenForo has a huge reservoir of smart admins who could turn into addon-developers, adding value to the product. I know that I would like to start developing addons, but with the the overall sophistication of XenForo's software (the way that it compiles templates, MVC, Zend Framework, Routes, etc.) I don't know where to begin. The type of documentation that is provided by WordPress and many other packages would make a world of difference.
I made the following for it and I must admit I'm a bit proud of it. I'm pretty stunned that Xenforo is so far behind on documentation.
It would be nice if some Xenforo rep could make some sort of statement on this so that we know that staff take this rather embarassing omission seriously.