My friend Heidi has (or had) a web page that only she knew the link to. And she posts things there that no one else can find, unless they, by chance, guess the url and find it. So you could try something like that, just for venting. Just give no one the address or LJ name. The only problem with LJ is that someone could randomly find it, but how likely is it for one of the people who shouldn't read it, randomly find it.