Hilkhot Listserve
(Jewish Laws of E-mail Postings)
Internet Torah:
And thou shall never repeat all that you heard just to concur or disagree,
or my wrath will be severe unto the third generation, yea, my wrath shall
be great.
Rashi:
Kema shene'emar, 'all that you heard' - This means never quote an entire
usenet newsgroup message, including headers. Rather, just add a few
lines of your own.
Rambam:
It is a precept not to waste bandwidth.This teaches us the value of
brevity. All those who know this, yet waste bandwidth despite this well
known fact, are ignoramuses and are not to be trusted.
R. Yosef Caro:
One must quote the name and date, but must never quote the Internet
transmission path, except on HoShannah Rabbah. One must always quote the
relevant part of the message, and have it spaced five characters to the
right. It is strictly forbidden to quote more than you write. It is
strictly forbidden to write less than 60 character lines. Writing lines
that are over 80 characters results in herem.
R. Moses Isserles' Mappah:
One can be lenient on line character length if it is denoted as being
an HTML file. It is well known that German Jews have the halakhically
acceptable custom of never writing lines _under_ 80 characters in
length, but other Ashkenazim should avoid this.