In the above, the `#ifdef'/`#endif' pair is a conditional compilation syntax from C; here, it implies that the text between (which is a {flame}) should be evaluated only if you have turned on (or defined on) the switch FLAME. The `#include' at the end is C for "include standard disclaimer here"; the `standard disclaimer' is understood to read, roughly, "These are my personal opinions and not to be construed as the official position of my employer."
Another habit is that of using angle-bracket enclosure to genericize a term; this derives from conventions used in {BNF}. Uses like the following are common:
So this <ethnic> walks into a bar one day, and…
Hackers also mix letters and numbers more freely than in mainstream usage. In particular, it is good hackish style to write a digit sequence where you intend the reader to understand the text string that names that number in English. So, hackers prefer to write `1970s' rather than `nineteen-seventies' or `1970's' (the latter looks like a possessive).
It should also be noted that hackers exhibit much less reluctance to use multiply nested parentheses than is normal in English. Part of this is almost certainly due to influence from LISP (which uses deeply nested parentheses (like this (see?)) in its syntax a lot), but it has also been suggested that a more basic hacker trait of enjoying playing with complexity and pushing systems to their limits is in operation.
One area where hackish 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 the notation 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 `Mail(1)' 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 `>' or `> ' became standard, perhaps owing to its use in `ed(1)' to 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.
A few other idiosyncratic quoting styles survive because they are automatically generated. One particularly ugly one looks like this:
/* Written hh:mm pm Mmm dd, yyyy by user@site in <group> */
/* ————— "Article subject, chopped to 35 ch" ————— */
<quoted text>
/* End of text from local:group */
It is generated by an elderly, variant news-reading system called `notesfiles'. The overall trend, however, is definitely away from such verbosity.