As it seems quite a lot of people think they can post anything and anyhow I've listed these basic rules to follow.
1) Respect other users/mods/admins. That means no insulting. Seems as if people are having a hard time understanding this. Do not insult in the chatbox, on the topics, in the PMs. Discuss your matters like normal, civilized people.
2) No spam-posts. Try to refrain from making useless posts. If the only thing you have to say is "ok" or "xD" then it's not worth posting. Double-posting will also be frowned upon.
3) Use English when making posts, or at least provide a translation (preferably in the same post). Mod applies should only be written in English.
4) Don't stray too far from the topic. That means no posts about weather on Moderator applies and no chatter about applies on the "How's your weather today ?" topic.
5) Don't bump/revive really old topics (not like we have any yet).
6) Don't send multiple PMs to Mods/Admins about the same subject. We understood the first time, it just takes a little while for us to find time for you.
7) Posts should not advertise any product/site/clan/server/whatever.
I believe this is it for now. Read the rules and (try to) memorize them.
Edit: Rule 7 added.