I think we already had most of the details, many of them in BOLD CAPS for good measure.
No, you haven't. The worst of it has never appeared in public, deleted or otherwise.
Fine. The thought is evidently forbidden, but merely alleged dangerous.
I see no good reason to call it "dangerous" - in the absence of publicly verifiable evidence on the issue - unless the aim is to scare people without the inconvenience of having to back up the story with evidence.
Some research says that lurkers make up over 90% of online groups. I suspect that Less Wrong has an even higher percentage of lurkers than other online communities.
Please post a comment in this thread saying "Hi." You can say more if you want, but just posting "Hi" is good for a guaranteed free point of karma.
Also see the introduction thread.