The Alex King interview was really interesting. I've used the Carrington theme on a website for a client. I appreciate the concept of Carrington, but in practice, it wasn't for me.

I don't really like the way that the granular structure creates so many extra files and folders. It seems to make things more complicated than it needs to be. But I did try out Carrington like a year ago and there wasn't much documentation, it looks like there is more documentation available now, which could make using Carrington simpler.

WordPress.org is a big site, it's hard to judge which sections are the largest. The support forum must have the most pages, followed by all the plugin, theme, and idea pages in Extend. The forums and Extend are largely powered by bbPress I believe, so bbPress must be the platform for at least a good chunk of the site.

The Codex is another big section of the site, and that is powered by MediaWiki. I wonder if the Codex would ever be migrated to WordPress if there was a robust wiki plugin?

My guess is that the rest of the website is powered by WordPress MU rather than the standard version of WordPress. And of course the latest addition to WordPress.org is Profiles, which is run on MU and BuddyPress. I'm looking forward to this section growing, hopefully BuddyPress will play a more important role on wp.org as the focus on the community expands.