One thing I didn't realize when I was a kid was how much my parents' friends knew about me. Once I came by a piece of extremely personal information about one of my friends which had been leaked at a council of moms. I was horrified for my friend that this datum had left the privacy of her home. This was in high school, which accounts for my ultimately self-conscious horror, but not, in my opinion, for the secret-sharing. Christians can and will pray for each other without the details of every situation.
There's a point at which the functions of our childrens' bodies, the misfirings of their minds, the falterings of their souls, their dreams and sins become no one's business but theirs and their parents'. That information belongs primarily to them, not us. Maybe I'm hung up on this because I'm a little overprotective of my own privacy and find myself wondering what my parents' contacts, with whom I still occasionally interact, know about my not-even-that-misspent youth. But there are already things I wouldn't "tell on" my kids. It goes beyond bathtub photos. I know my daughter wouldn't want me ratting her out on certain topics and events to her grandma or friends, and she's six.
When in possession of a funny, cathartic, or burdensome story, parents should consider carefully their children's confidence in them before they start talking shop. What is to be gained by sharing this information? Does it really need to be shared, and if so, how much of it? What would my child think if she knew this person knew? I'm not saying we can't talk; just that we should remember the power of our words.