Swearing is allowed within reason. Don't use it excessively. The definition of "Excessive" is left to any mods that are online at the time. If you are unable to express yourself without the use of heavy profanity you should consider improving your communication skills.
Losing games, particularily to bad draws can be frustrating. Chat is not a good place to vent that frustration.
Non-english languages should be in whisper or private channels. This is due to not being able to moderate it. (Consider trying /channel languagename )
All decisions of mods are final.
Your name will always appear highlighted for you. Other people will see their name highlighted. You don't need to do anything to cause this.
You can post links by including the full url, including the http://
You can click on someone's name to whisper to them. Also the h/w next to their name will take you to their have/want list.
You can use some html, such as ™ or æ
To use an "&" use "&" to avoid it being interpreted as an html character.
All messages including whispers are stored in the DB. Admins have access and could read those messages. If this is a problem don't send the message through the ladder.
The chat's help button provides useful information including all emotes.