Sol de Zuasnabar Brebbia / Getty

Veronica Belmont, a product manager at Adobe Spark, was riding the train down to Silicon Valley, doing some work on her phone, when dozens of teenagers plopped down into the seats around her. Within moments, her phone began blowing up. She received an AirDrop request containing an image of several boys’ Bitmoji characters dressed in chicken suits. A group of them snickered as she opened it and looked around. Belmont was confused. “I was like, I don’t know what this means!” she told me.

Anyone who has accidentally left their AirDrop settings open around a group of teens is likely familiar with the deluge of memes, selfies, and notes that arrives so quickly it can often freeze your phone. “Another day another group of french teens trying to AirDrop me memes on the subway,” one woman tweeted. “In a crowd of teens and they keep trying to AirDrop me memes!!!” said another. One young Twitter user joked that she was going to a music festival last weekend “just to AirDrop.”

AirDrop is a file-sharing feature on Apple devices that lets users send photos, videos, contacts, links, and more via a combination of Bluetooth and Wi-Fi. Phones with AirDrop enabled can exchange files from up to 30 feet away, whether or not they’re in each other’s contact lists. Many adults use AirDrop to share files one-on-one, but teens have embraced mass image sharing via AirDrop for years. As more teens get their own iPhones and a rising number of schools crack down on social media, AirDrop culture has gone mainstream—and more adults are getting caught in the crossfire.

It works like this: Once there’s a critical mass of people around, usually enough so that it’s not immediately clear who an AirDrop came from, teens start dropping photos, memes, selfies, and more to every open phone around. Teenagers will usually change the names of their iPhone to something anonymous or funny to compound the joke. “I used to have the name ‘Momo Challenge’ for my phone,” says Ryan, a 17-year-old in California who, like all teenagers interviewed for this story, is referred to by a pseudonym. “Sometimes I’ll do my country name from Model UN, or something related to the situation I’m in. I used to have it named Donald Trump, then I’d send crazy-liberal memes.”

The photos swapped are usually memes or odd pictures teens find on Google Images. “It’s a very specific type of pic that gets AirDropped,” says Henry, a 16-year-old in Pennsylvania. “It’s funny to look down at your phone and see something random.” Because the recipient can only see a smaller preview of the image before accepting the request, anything too intricate doesn’t work. During assemblies or classes, teens will AirDrop reactions to what the teacher or presenter is saying. Belmont said when she was giving a presentation to a bunch of young girls interested in STEM two weeks ago, she received a bizarre meme AirDropped to her computer mid-talk. She worried they were making fun of her.

Naturally, some teens push the boundaries of what’s acceptable to share. It’s not unheard of for kids to blast out nudes (of themselves or others) and porn. Some kids bully one another by distributing compromising or unflattering photos of their classmates. Because AirDrop is a feature that is automatically included on every iPhone, not a social-media app, there’s no moderation or reporting tools, nor can anyone get banned from the service for sharing graphic or sexual images like you could on Instagram, for instance.

Some schools have also had problems with students cheating via AirDrop. Sam Bendinelli, a public-high-school teacher in New Jersey, told me that students sometimes send copies of tests, homework, or answers to quizzes via AirDrop during class or free periods. He and other teachers have begun to crack down on students having their phones out in order to thwart this sort of sharing. “If I see a phone out now, it doesn’t matter what excuse you give me. I’m voiding that test because [cheating] is too easy,” Bendinelli said.  

But Bendinelli said most of the images students drop to one another aren’t anything problematic. “It’s primarily a social-networking thing ... I would estimate 80 percent of AirDrops at school are memes and fun things to pass around. It’s like a chat room where some people are anonymous, some have names attached,” he said. Bendinelli also said that students go out of their way not to include teachers. Adults are more likely to have earnest names on their iPhones, instead of jokes and memes, so some kids will take pains to avoid them.

Teens say that sending things out via AirDrop is superior to social media or text messaging because you don’t need to have a person’s username or phone number to share something. It’s far less time-consuming than sending a text or a DM, and you don’t need to create a giant group chat to send things out en masse. You can also stay anonymous. AirDrop is like a roving ephemeral message board that anyone in the area can contribute to.

Memes blasted out via AirDrop can be a beacon for other teens in the area. “It’s a way for mass communication based on location,” says Tiffany Zhong, the founder of Zebra IQ, a Generation Z research firm. “There’s always going to be people you don’t know at events, parties, or at school ... You just want to see who else is around.” Plus, Zhong says, kids know that the people AirDropping things back and forth are other teenagers whom they probably have something in common with. It’s like starting a big group chat with everyone around you that stops as soon as you walk away.

Ryan says the moment she and her friends step into a model-UN competition or wait for a concert to start, they get the AirDrop going. She sends memes and photos of strange animals, and sometimes she’ll include her Instagram handle. Ryan says she has made several new friends this way. “I have about 35 followers on Instagram from AirDrop,” she says. “Considering ... they follow you not even knowing your face or who you are, it’s kind of a lot.” Ryan has five Instagram accounts but says the only handle she lists is her public personal one.

Some kids AirDrop out their Snapchat code, or a selfie with their Instagram handles inviting recipients to message them if they’re interested in a date. Ryan says she’s followed a few people on Snapchat whom she discovered via AirDrop. “It’s just a good way to expand your circle,” she says.

Adults who stumble into an AirDrop ring usually feel like they’ve entered the wrong room. It can feel awkward, and grown-ups often aren’t sure whether they’re being trolled. Zhong, who is 22 years old, says she’s seen some friends AirDrop people repeatedly in an attempt to crash their phone. The humor comes from watching the poor souls’ reactions as their phone stops working, or their confusion at being bombarded with an endless stream of obscure references.

But Alex, an 18-year-old, says he doesn’t think adults should be intimidated. If anything, he says, he and his friends go out of their way to avoid adults since they probably wouldn’t get the humor anyway. Still, Bendinelli says it’s better to just hold off and let the kids have their thing. He turns his AirDrop settings to “off” during school hours and recommends other teachers do the same. If nothing else, it will at least help preserve their phones’ battery.

But for adults who encounter a cluster of AirDrop swaps and do want to participate, selecting the right image to drop back is key. When a Twitter user named Kyle Hammy was being “fully harassed” by teens on public transit, as he posted last October, he repeatedly struck back with a secret weapon: an image of a woman in a Finding Nemo costume, on ice skates.

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