I'd estimate that something like a third of what people had to say was confessions. These weren't usually "I shoplifted" type of confessions, but closer to the category containing "I often feel like I'm obligated to do X, but can't because of Y" or "I don't fit social construct Z and I'm afraid I would be ostracized if my friends and family knew."

I think this was common enough that, if someone did want to use this sort of information to control us, they could get some serious mileage out of it. I just don't expect this to happen because there's not much evidence of any unethical manipulation.