NEW YORK — Janell Burley Hofmann honored her 13-year-old son’s “maturity and growth” at Christmas with his first iPhone, but it came with strings attached.

Eighteen strings, to be exact, in a written code of conduct that placed the mommy blogger at the center of the debate over how parents should handle technology in the hands of their teens, especially younger ones just entering the frenetic world of social networks and smartphones.

Thousands of people, including those bemoaning too much helicopter parenting, commented and shared the funny, heartfelt agreement posted at the holiday by the Cape Cod, Mass., mom of five. The interest crashed her website and led her to appear with her eldest, Gregory, on morning TV.

Hofmann’s first order of business: “1. It is my phone. I bought it. I pay for it. I am loaning it to you. Aren’t I the greatest?”

She included caveats that some parenting and tech addiction experts consider crucial in easing new entrants onto Facebook, Instagram and shiny new mobile devices:

You must share passwords with a parent, answer their calls, hand over said device early on school nights and a little later on weekends. You must avoid hurtful texts and porn and pay for a replacement if your phone “falls into the toilet, smashes on the ground, or vanishes into thin air.” Of the latter Hofmann advises her teen, “Mow a lawn, stash some birthday money. It will happen, you should be prepared.”

Hofmann said in an interview that she decided on the contract as she pondered the power of the technology she and her husband were about to plop into their son’s world. She was looking for a way to be present in his phone use without being a “creeper,” his word for stalky, spying parents.

She wasn’t surprised that her list, which Greg agreed to, resonates with other parents. It also resonates with psychologist David Greenfield, a technology addiction specialist in West Hartford, Conn.

“We have ritualized the gift of the smartphone,” he said, yet many parents don’t have the know-how, stomach, time or interest in actively guiding kids when they first jump into digital life. For some parents, he said, it’s only when things go horribly wrong that attention is paid.

He knows of parents who have gone so far as to jam all Internet and cell phone signals at home when they couldn’t get their kids to power down. Police in Rocklin, Calif., said two girls, ages 15 and 16, used a prescription sleeping medication recently to spike the milkshakes of one’s parents so they could log onto the Internet after 10 p.m.

Greenfield recommends contracts like Hofmann’s, if parents follow through. Others creep using apps and monitoring software. He thinks that’s fine, too.

There’s little data broken down by age on the number of Internet users whose lives are negatively impacted by smartphones, tablets, laptops and other technology, Greenfield said. In the general population, studies range from 1 percent to 10 percent of users whose digital habits interfere with their lives. Greenfield estimates the reality is somewhere between 2 and 6 percent.

Hofmann was looking for a way to open the conversation with her son. Many other parents are, obviously, concerned as well about what their teens are doing online, but also what is being done to them.

In a recent report from the Pew Internet & American Life Project, 81 percent of parents with online teens said they are concerned about how much information advertisers can learn about their kids’ behavior and 72 percent said they’re concerned about how their children interact online with people they don’t know.

Nearly 70 percent said they’re concerned about how their children manage their reputations online and 57 percent of kids ages 12 and 13 said they’re very concerned about it.

The report said parents are being more proactive, not just relying on parental-control tools such as browser filters. An increasing number are joining their kids on social media, but older parents may be approaching their kids’ lives there with the wrong emotional filters.

“We see it as a separation from social behavior. They see it AS social behavior,” Greenfield said. “I’m not sure we’re going to be able to bridge that difference generationally.”

More tech abuse education needs to be done in this country before teens are actively engaged, he said. In parts of Europe and Asia, for instance, kids learn how to handle their digital lives as formal training in third or fourth grade.

“Here they think of it like it’s part of their body, and they treat it that way,” Greenfield said.

Hofmann’s contract is her own attempt at education. “Don’t take a zillion pictures and videos. There is no need to document everything. Live your experiences. They will be stored in your memory for eternity.”

And she gets downright inspirational toward the bottom: “Leave your phone home sometimes and feel safe and secure in that decision. It is not alive or an extension of you. Learn to live without it. Be bigger and more powerful than FOMO — fear of missing out.”

Hofmann also urges her boy to, “Keep your eyes up. See the world happening around you. Stare out a window. Listen to the birds. Take a walk. Talk to a stranger. Wonder without googling.”

And her final word: “You will mess up. I will take away your phone. We will sit down and talk about it. We will start over again. You & I, we are always learning. I am on your team. We are in this together.”

Aisha Sultan in St. Louis studied parenting in the digital age as a Knight Wallace Fellow at the University of Michigan. As parents, she said, “We’ve sort of hit a tipping point. The conversation has shifted from wow, isn’t all this technology cool to wow, how do we control it? We can’t eliminate it completely.”

But parental frustration is mounting, Sultan said. She cited last year’s case of a father who shot up his daughter’s laptop over a profanity-infused Facebook rant against her parents. He recorded the act and earned more than 23 million YouTube views for his trouble.

Before the conversation with our kids begins, Greenfield said, parents have to deal with their own digital obsessions.

“Parents have to have limits, too,” he said. “We have to be brutally honest with ourselves on our own use and abuse.”