From Jimbojw.com

Version 0.4.3 of the ArticleComments Extension has been released and is available for download.

This minor release adds a long-awaited (and frequently requested) new feature. By adding the text "<!--COMMENTS_ABOVE-->" or "<!--COMMENTS_BELOW-->", you can force ArticleComments to inject new comments before or after those markers respectively.

This means it is now possible to have comments listed reverse chronological order, newest at the top. To do so, just add "<!--COMMENTS_BELOW-->" at the top of the Talk page.

For example, a talk page might start off with this:

<noinclude>Comments on [[{{PAGENAME}}]]
<comments />
----- __NOEDITSECTION__</noinclude>
<!--COMMENTS_BELOW-->

An additional benefit of this new insertion feature is that ArticleComments can be used with WikiArticleFeeds to give RSS feeds of comments on a given article.

To do this, the Talk page should start out like this:

<noinclude>Comments on [[{{PAGENAME}}]]
<comments />
----- __NOEDITSECTION__<startFeed /></noinclude>
<!--COMMENTS_BELOW-->
<noinclude><endFeed /></noinclude>

Note: Of course, if you want to retain the normal chronologically ordered list of comments, you'd use COMMENTS_ABOVE there instead of COMMENTS_BELOW.

To make the above the default in your wiki, log in with a user with Sysop privileges and edit the [[MediaWiki:Article-comments-talk-page-starter]] article to contain whatever starter text you like.

Enjoy! As always, I'll be happy to answer any questions.