Banned from Mebeam / Private on Mebeam / Sound on Mebeam

I got banned from Mebeam, with the message "Stop being a Jerk". The only thing I'd done was reply "Eeew!" to someone (invisble) who asked if I used my wife's panties. Was that a nono?

How do you get unbanned? Membeam is very opaque about who or what it's for. All the help is technical.

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How does "Private" work in Mebeam? There's a link for it on each pane, but it doesn't seem to do anything. When someone suggests going private, how do you do it.

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What's the story about sound on Mebeam? Mine is always perfectly silent.