Message Boards are not really "chat", but they can be an excellent and fun way for new users to connect with others.

Advantages:

• No set time to read or post entries, so you don't have to worry about time schedules or zones.
• No problem "keeping up" with the often quick pace of chat - read and post at your own speed.
• Get to know the other people on a message board gradually, and (if true chat is available) find out if they're a group that you'd enjoy chatting with.
• Topics you get involved in are *your* choice

General Rules for Message Boards:

• Don't SPAM! Spamming in message boards is generally off-topic posts (messages) advertising a product, web site, or anything else.  note: if the product, web site, etc is ON-topic, it may not be considered "spam". For example, if there was a topic already started in a message board that says, "What does ROFL mean?", I could reasonably post a link to this Chat101 site in response.
• The Chatiquette, No-Nos and Chat Terms topics in this site ALL apply to Message Boards as well - don't use all CAPITAL letters, don't flame, play nice, etc.
• Stay within the guidelines of the community (G rated for example), the general message board code of conduct (no posting of other people's picture or personal information), and the law (no child porn, copyrighted material, etc)

Special Message Board Issues:

• "Thread" is the term used to refer to the original message topic and the replies. Unless it's a very informal message board, stay within the thread topic. If you want to bring up another topic, start a new thread.   Changing the topic of the thread is often called "stomping", and is discouraged.
• Many message boards have their own graphics/emoticons available - or none at all. See if there is a "help" available for the specific message board.
• Some message boards (like the ones in msn communities) are very advanced - you can alter the appearance of your font style, color, size, background and more. Don't feel that you *have* to use these (or any other advanced) features of a message board. Simple messages are just fine.
• Many message boards allow you to insert or attach pictures and/or files (photos, graphics, documents, etc). Be sure you reduce the size of your graphic to a reasonable (I'd suggest less than 50k max - the smaller, the better) size before you include or post it.  note:  I know msn web communities has a limit to the total size of graphics you can post - not sure about other message boards. 
• Your E-mail address may automatically be included when you post a message. If you don't want it to be, see if you can change personal settings.  You may also want to alter your e-mail address (like  yourname@ nospamhotmail.com) on general message boards to take the first step to confuse e-mail harvesting software.  If you want people to e-mail you, though, be sure that your e-mail address is shown somewhere in your message post.