For the "newbies" here are some suggestions. These are not "rules" and you should feel free to disregard them. I'm offering them simply because Disboards chat can seem very intimidating (I'm still intimidated by it) and I hope these alleviate some "newbie" apprehension.
Use
big font sizes. Colored fonts also help.
If you say something and it doesn't get acknowledged, please don't get put off. I can't tell you the number of times I've said something that wasn't acknowledged. It likely means the conversation is moving along quickly and your question didn't get noticed or, if it did, some of us got distracted before we could respond to it (chat moves very quickly and some of us have short attention spans). No one in chat means to ignore anyone (though there is an "ignore" feature we can push when someone tries to be annoying

).
If you don't understand one of the many "inside" jokes, please ask. Some of us have actually met in the real world - imagine that - and we have known each other for some time. Even so, we were all newbies once (well, except for Kevin, who, by definition, can't be a "newbie") and want everyone to feel welcome.
Food will be discussed repeatedly. Photographic technology will likely be discussed. Tuba concertos are sometimes discussed.

In other words, the discussions often have utterly nothing to do with Disney. If you have a specific question about Disney ask it. Someone will try to answer it but general questions about Disney ("how often do you go to WDW") usually receive only a few short replies.
Please don't ignore your significant other(s) during chat, especially as the midnight hour approaches (for those of us on EST). I speak from personal experience.

If you hear a heavy sigh from the person sitting behind you on the couch, just say, BRB (be right back).