There's comfortable oversharing and then there's the oh-fuck-did-I-actually-say-that? oversharing. That second kind is kind of like scraping cells off your inner skin and holding them up for inspection. Jesus, that's a terrible metaphor, but I figure I'll just leave it up anyway.
I want to make my living oversharing, in a sense at least. That's where the memoir stuff comes in. Then there's the fiction, which is oversharing of a different type. I mean, if you write something, that means you've thought it, no matter how seemingly terrible or embarrasing. Even if it's just your character thinking or doing something, it means that's gone through your head too.
Secrets, I think, are more destructive than honesty. Usually.