One area where conventions for on-line writing are still in some flux is the marking of included material from earlier messages -- what would be called `block quotations' in ordinary English. From the usual typographic convention employed for these (smaller font at an extra indent), there derived a practice of included text being indented by one ASCII TAB (0001001) character, which under Unix and many other environments gives the appearance of an 8-space indent.
Early mail and netnews readers had no facility for including messages
this way, so people had to paste in copy manually. BSD
was the first message agent to support inclusion, and early Usenetters
emulated its style. But the TAB character tended to push included
text too far to the right (especially in multiply nested inclusions),
leading to ugly wraparounds. After a brief period of confusion
(during which an inclusion leader consisting of three or four spaces
became established in EMACS and a few mailers), the use of leading
> became standard, perhaps owing to its use in
display tabs (alternatively, it may derive from the
> that some
early Unix mailers used to quote lines starting with "From" in text,
so they wouldn't look like the beginnings of new message headers).
Inclusions within inclusions keep their
> leaders, so the `nesting
level' of a quotation is visually apparent.
The practice of including text from the parent article when posting a followup helped solve what had been a major nuisance on Usenet: the fact that articles do not arrive at different sites in the same order. Careless posters used to post articles that would begin with, or even consist entirely of, "No, that's wrong" or "I agree" or the like. It was hard to see who was responding to what. Consequently, around 1984, new news-posting software evolved a facility to automatically include the text of a previous article, marked with "> " or whatever the poster chose. The poster was expected to delete all but the relevant lines. The result has been that, now, careless posters post articles containing the entire text of a preceding article, followed only by "No, that's wrong" or "I agree".
Many people feel that this cure is worse than the original disease, and there soon appeared newsreader software designed to let the reader skip over included text if desired. Today, some posting software rejects articles containing too high a proportion of lines beginning with `>' -- but this too has led to undesirable workarounds, such as the deliberate inclusion of zero-content filler lines which aren't quoted and thus pull the message below the rejection threshold.
Because the default mailers supplied with Unix and other operating systems haven't evolved as quickly as human usage, the older conventions using a leading TAB or three or four spaces are still alive; however, >-inclusion is now clearly the prevalent form in both netnews and mail.
Inclusion practice is still evolving, and disputes over the `correct' inclusion style occasionally lead to holy wars.
Most netters view an inclusion as a promise that comment on it will immediately follow. The preferred, conversational style looks like this,
> relevant excerpt 1 response to excerpt > relevant excerpt 2 response to excerpt > relevant excerpt 3 response to excerpt
or for short messages like this:
> entire message response to message
Thanks to poor design of some PC-based mail agents, one will occasionally see the entire quoted message after the response, like this
response to message > entire message
but this practice is strongly deprecated.
> remains the standard inclusion leader,
occasionally used for extended quotations where original variations in
indentation are being retained (one mailer even combines these and
|>). One also sees different styles of quoting a number
of authors in the same message: one (deprecated because it loses
information) uses a leader of
> for everyone, another (the
most common) is
> > > > ,
> > > , etc. (or
>>>, etc., depending on line length and
nesting depth) reflecting the original order of messages, and yet
another is to use a different citation leader for each author, say
(preserving nesting so that the inclusion order of messages is still
apparent, or tagging the inclusions with authors' names). Yet
another style is to use each poster's initials (or login name)
as a citation leader for that poster.
Occasionally one sees a
# leader used for quotations from
authoritative sources such as standards documents; the intended
allusion is to the root prompt (the special Unix command prompt issued
when one is running as the privileged super-user).