I'm thinking that in real chess, the "silence is golden" rule applies, with absolute minimal banter. I'm new to chess and naive, so I have a "new" look at silence in regards to on-line games - specifically the turn-based ones. Not the Live! Chess or any other versions on chess.com.
My rationale is that you are not being verbal with the person. My take is, someone can type all they like in the chat box without it affecting me personally - I won't get intimidated by 12 pitch Times New Courier font!