How to act and what to expect. A specialized room is different. One hello to everyone will usually do, other wise all you would see would be screens of hello and goodbye. All uppercase letters is considered yelling and rude, you will notice everyone uses lower case.
All capitals are also harder on the eyes.
Excessive use of action, sound, color or any other method of highlighting your lines is annoying to most users and makes you look insecure because you no one will pay attention to you otherwise, try talking about something that will interest everyone. If you enter during a rather intense conversation no one may have anything to say to you right away. Sit back get a feel for what is going on then join in if you can add something, don t expect a total recap of what already passed just because YOU have arrived. Someone may be willing to update you in private, but that is up to the individual. It is not usually because they don t like you.