Also try and keep a friendly "tone" such as when you joking about something use a smiley face or similar and always try and help newer people out.
I would prefer a forum where you don't have to use emoticons, that the context of the joke, people's judgement of personality and their good sense of humour mean you don't need to state a joke. When you tell a joke do you announce that it's a joke, after the punchline? You shouldn't.
Problem is, posts get misconstrued - better use a smiley.