Q. What conventions and considerations should people follow before reading someone's text conversations?

A friend of mine told me that she reads all of her 17-year-old's text messages - both the ones he sends and the ones he gets - after he goes to sleep at night. A few days later, my grandson was fooling around with my phone - checking out the music, the pictures, etc. - and then asked me a question about something that he could only have read about in one of my text conversations. I was quite upset and I told him the same thing I had told my friend: I thought it was morally reprehensible.

I said it was an invasion of a person's privacy to read those messages without getting permission. He told me that he would not look at my messages again, but that I was "way overreacting" and that "everybody does it."

Am I overreacting? Is there no privacy in our glorious new Communication Age? What are the rules?

A. The rules are the same as they've always been. It was just as wrong for your friend to read her child's text messages as it was for your grandson to read yours, or for a parent to have read her daughter's diary 50 years ago. And it was wrong for the same reason: They each invaded someone's privacy, because they did it without their permission. They were, in short, disrespectful, which a parent - or a grandson - should never be.

Although "morally reprehensible" is a grave charge to make, it applies to your friend far more than your grandson. She clearly knew that she was doing something wrong, because she waited until her son went to sleep before she read his messages. Your grandson, however, simply made a mistake. Many teenagers read each other's texts and even their e-mails, because no one ever told them that they aren't like postcards or billboards; they're private communications, like the letters that come in the mail.

If your grandson still believes you are overreacting, tell him that maybe he's right after all and that you might start reading his texts, too. And then watch him blush when he remembers the messages he sent to that pretty girl he met at the beach last summer.

Teenagers often brag when they write to each other, and they also exaggerate, gossip, say mean things and say things they don't mean. Sometimes, they pretend they're a little braver, sexier, smarter or more interesting than they are. They do this because they're trying to make up for inadequacies they see in themselves, because they haven't learned to be discreet yet and because they can't believe that anyone aside from their friends will ever see the comments and the raunchy pictures they post on Facebook. As young people eventually discover, a smart boss always checks out an applicant's online history before she offers him a job.

Smart parents are careful, too, or at least they should be. Many of them use Facebook and other Web sites to teach family values, simply by telling a child that they'll be checking his or her Facebook page occasionally to make sure the child is not bullying, spreading rumors or bashing anyone. Some parents also tell their child that they'll be checking his or her text messages occasionally, because there are so many temptations and weirdos out there, but emphasize that they'll always inform the child before they do it. As one wise father said, "I trust my daughter; it's the world that I don't trust."

Nothing is written in stone, however. There are times when a child's behavior becomes so odd, so contrary - so impossible - that parents, and sometimes grandparents, have to step in. In such cases, you might monitor a teenager's driving by slapping a gizmo on the car to see where he drove and how fast, take him to the doctor to make sure his blood chemistry is good and he can pass a drug test, or put a control on the computer to limit the amount of time he uses it.

Questions? Send them to advice@margueritekelly.com .

Beyond the Almanac

For other solutions to the many electronic problems that can affect families, consider reading the updated edition of "Kids, Parents & Technology," an e-book by Eitan D. Schwarz (MyDigitalFamily, $13). It's not perfect, but it should be helpful if you're patient, left-brained and more tech-savvy than most of us.