So here's what's up:
I read a WPMU Manual article, and I end up with a question. A clarification from something I'm confused about from the article.
But there's no question / comment form! I'd have to ask you somewhere else, but then you're lacking the proper context, AND future readers don't get to view the content.
I know, I know. You want to keep the manuals clean and pristine. No problem! You could create a "Got a question? View and ask questions about this article >>" button, and load the content with Ajax.
Finally, to make sure the most useful question/replies (comments) are seen most frequently, create a "this was helpful to me" button, and show the best ones at the top.