This article is from the Rialto FAQ, by Richard "Pug" Bainter pug@pug.net with numerous contributions by others.
The short answer is that messages propagate from one system to another
at varying speeds, and therefore an answer posted on a well-connected
machine may arrive at a less-well-connected machine before the
question does. The longer answer requires paying attention to the fact
that the Rialto is both a Usenet newsgroup and a mailing list, and the
gateway between them is another place where the ordering of messages
can be scrambled. There is nothing that can easily (read
cost-effectively) be done about the scrambling of message order (it
would require a complete redesign of the Usenet newsgroups, just to
start with) so please don't ask. This message scrambling, by the way,
is a good reason to paraphrase or quote just enough of the message you
are answering to make clear what you are talking about.
 
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