The Discussion threading allows the Talk (discussion) pages to use a
threading like structure, posting replies and new threads by default instead
of free-form text.
I finally got around to greatly simplifying the installation hassle by
reducing required patches and testing for both 1_9_3 and 1_10_0 and have
updated the installation instructions, patches, and even patched include
files for these versions available for download.
While this is not true threading, it takes you a long way there until proper
threading can be introduced.
For further details, see:
http://www.mediawiki.org/wiki/Extension:DiscussionThreading
Jack D. Pond
"It is my ambition to say in ten sentences what others say in a whole book."
-- Friedrich Nietzsche