> Or do a lot of these threads seem to hang off of
> other non-related threads?

Because the newsgroup synchronises with an email listserver, I think
what you are seeing is the result of laziness by some posters.

Rather than starting new threads by starting a new blank email, people
sometimes hit reply and then change the subject. This of course
leaves the internal references in place, making it impossible for the
news or email software to link the message threads properly.

As a warning against this practise... When attempting to review items
on the list that need attention I often view the messages by
thread. If your message is buried under some other topic it will
NOT get attention and your question may be missed.

--
Geoff Worboys - TeamIBO
Telesis Computing