Here's a summary.

o Learn about Usenet before you post.
o Follow S.C.J.P and read news.announce.newusers.
o Use the appropriate newsgroups: Israeli politics belongs on
  "soc.culture.israel" or "talk.politics.mideast"; Holocaust denials belong on
  "alt.revisionism"; Messianics belong on "alt.messianic"; Middle east
  politics belongs on "talk.politics.mideast"; discussions about Turkey and
  Armenia belong on "soc.culture.turkish"; general childrearing discussions
  belong elsewhere on the misc.kids tree; and general Jewish discussions
  belong on soc.culture.jewish.
o Know your audience and make your posts understandable.
o Trim quoted material whenever possible, and try to ensure there is content
  in your posting (except, perhaps, during the month of Adar)
o Don't challenge the validity of Judaism or assert the superiority of other
  religions  and prophets thereof.
o Don't write "lashon hara" [true slander] or "motzei sheim ra" [false
  slander].
o Don't start posting until you've finished reading the FAQs posted to this
  newsgroup.