What is socially acceptable to blog about? That's one of the questions I have pondered when everyone can be a publisher, and when most in my social circle are publishers/bloggers.
And the answer is simple: if you are at a private event, among your friends, then everything is off-the-record you do not publish anything that could embarrass anybody, or republish anything that was said/done unless you have an agreement to do otherwise.
This is something we, as a society, are going to have to start talking about. For example, if I go to a meeting, I may cover the presentation and the questions. I do not write about the little meeting after the meeting were attendees come forward to ask the questions they did not want to ask publicly. Neither do I blog about the after the meeting gossip session that inevitably occurs on the subway ride home.
There has been some discussion about libel, but almost none about privacy.