Zach Lewis swears he was just resting his eyes.

But when a fellow student at Stowe Middle High School in Vermont surreptitiously snapped his picture during English class and shared it with the school’s “sleep account,” it was hard to dispute the evidence. There he was, book open, lids shut.

After Zach was tagged in the photo on Instagram, he sent a message to the people who manage the account to remove it. They quickly deleted it. “I wasn’t worried about a teacher seeing it,” Zach, 16, said. “It’s just embarrassing to have it up there.”

But that didn’t stop him from secretly photographing another student who fell asleep in English, then submitting it to the account for publication.

“Everyone,” Zach said, “has been trying to catch each other.”

Part prank, part extracurricular documentary project, sleep accounts are among several types of so-called school accounts that have proliferated on Instagram in recent months, as students have returned to classrooms following two disrupted academic years. After many months of pandemic-mandated remote instruction, teenagers have come to regard such banalities as their classmates eating, slouching and parking badly as fodder for amusement — and, of course, content.

“Now that we’re all in person again, we realize there are so many things we missed out on seeing last year,” said Ash Saple, a 17-year-old junior at Hamilton Southeastern High School, in Fishers, Ind.

At Ash’s school, there have been accounts capturing good parkers, bad parkers, cute outfits, shoes, fast walkers, slow walkers and red-haired students. Compared to the spicy rumors shared by fictional students (and teachers!) on “Gossip Girl,” the images are rather tame. (Even when you take into account the odd accounts that delight in showing students’ feet under bathroom stalls.)

Ash herself runs an “affirmation” account, where she makes and posts funny, glass-half-full memes that play on her school’s inside jokes and culture. Her first post showed a car parked off-center in a school lot. “I will not end up on @hsebadparking,” the affirmation read.

The students behind these accounts say they are mostly a harmless trend, predicated on the novelty of being in the same physical space as their classmates again. There is also a poignancy to the accounts; as many students head out for winter break amid a national surge in Covid-19 cases, there is some uncertainty about whether in-person instruction will resume in January.

“On your computer in your bedroom, you can’t see people napping and you don’t see how badly people park their cars because no one left their house,” Ash said. “There are so many things that you forget about that are just normal things that we’re now able to notice.”

The account that posted the photo of Zach appearing to doze off in class in Vermont is run by two sophomores, Teague Barnett and Andrew Weber, both 15. They had seen on Instagram and TikTok that other students at schools had started slouching and “bathroom feet” accounts.

They decided to create one themselves: a sleep account in which anyone who wished to have their photo removed would be respected. “There is a high school cliché that everyone is falling asleep in class and this account is here to poke fun at that,” Andrew said.

The boys see it as a lark. “A lot of the things that are fun to high schoolers are risqué and things parents wouldn’t be OK with,” Teague said. “But this is a good way to escape and play a little prank and no one is getting hurt.”

Parents seem to agree. “It’s great to have the kids back in school and able to poke fun and have a good chuckle,” said Andrew’s father, Chris Weber. He sees it as a reflection of a generation that has grown up with smartphones and social media, observing and being observed.

“They document their entire lives,” Mr. Weber said. “And they’re very comfortable being seen by their peers at almost any moment.”

Jacqueline Montantes, a 16-year old high school sophomore in Seguin, Texas, was recently featured on her school sleep account after a long night of studying. She’d made it through history class, but algebra II did her in.

When she saw the picture on her school account, she thought it was funny. “But I was scared my coach was going to see it,” said Jacqueline, who is a member of the Seguin Starsteppers, a drill and dance team. (If the coach saw it, she didn’t say so.)

Later, she made a TikTok that showed some of the sleeping photos from the account. “Can’t even be comfortable in class anymore,” she wrote in the video’s caption.

That sense of being constantly monitored has also hit Maggie Garrett, a 15-year-old sophomore in Atlanta. “I think it’s fun, but it keeps everyone on edge,” she said. “No one wants a bad picture of themselves slouching or sleeping or eating being posted.”

Last month, Maggie made a video of her and her friends, sitting with ramrod posture at a lunch table at school. She shared it on TikTok with the caption, “Us trying not to get posted on our schools slouchers Instagram account.”

“It got quite a lot of notice,” Maggie said, “and my friends were like, ‘Oh my gosh, I’m featured on a TikTok that’s getting a lot of views.’”

At least they were sitting up straight.

This article is part of the On Tech newsletter. Here is a collection of past columns.

Big Tech got bigger-er and stronger in 2021. The empires of technology also appeared more vulnerable than ever to the forces of regulation, competition, a complicated public mood and perhaps hubris.

Yup, this is a contradiction. But this stronger-but-weaker phenomenon for Big Tech is likely to continue in 2022.

Behind this trend is the same question I keep asking in this newsletter: Are American technology superpowers including Google, Amazon, Apple, Microsoft and Facebook invincible in a way that prior generations of corporate titans were not?

First, here’s a glimpse at ways that Big Tech reached the stratosphere in 2021. Apple, already the world’s most valuable business, is close to reaching an unimaginable stock market value of $3 trillion. That’s about eight Walmarts, or more than the value of the entire German stock market.

Amazon is so consequential in the U.S. job market that the company’s hourly pay has nudged local businesses to increase their rates, which has pushed up the paychecks of many Americans who don’t work for Amazon. When Facebook and its other apps blinked off briefly this fall, the outage showed how much of our lives and commerce rely on a single company.

This year, American tech powers were involved in U.S. drug policies, Russia’s presidential election and ethnic violence in Ethiopia. Tesla’s Elon Musk — his company is not technically considered Big Tech but its stock market value and influence make it an honorary member — was recently named Time’s Person of the Year.

This is familiar territory to many of you. Technology is one of the most consequential forces in the world, and so are the leading lights of technology. These tech empires’ combination of wealth, importance in the economy, huge numbers of users and global influence is perhaps something we’ve never seen before.

But at the same time that Big Tech grew richer and even more consequential, there are more stresses on their empires.

China’s government was anxious enough about the power of the country’s tech superstars that it cracked down on some popular digital services. In London, Brussels, Seoul, Washington, Tallahassee and — OK, just about everywhere — regulators and lawmakers are trying to erect new guardrails to control what they see as pernicious effects of tech companies’ power in our lives.

A lot of this activity might be go-nowhere bluster or ultimately prove relatively inconsequential. But when elected leaders turn against an industry, it is often a reflection of the popular mood. And it’s a good bet that they won’t turn sunny again soon.

And while the Big Tech giants remain profitable and growing, there are signs of weakness there, too. Jeff Bezos stepped aside as Amazon’s chief executive this year and some other tech bosses quit, too. Once a company gets big, it might be less fun to manage the messes.

Mark Zuckerberg seems worried about Facebook and its ability to stay relevant with young people. And big ideas in food shopping during the last two years came not from Amazon but from Instacart, fast-delivery start-ups like GoPuff and even Walmart. Americans spend more on groceries than nearly anything else, and Big Tech is largely a side show.

Feelings about tech companies and tech personalities are also growing more complicated. People often love or rely on tech, but they sometimes also feel yucky about it.

The latest obsession in the tech industry are cryptocurrency start-ups and related companies that imagine a future of the internet that would be less dominated by corporate control. This feels, in part, like a crisis of confidence about technology’s foundations from inside the machine.

Empires don’t tend to last forever, although many of the Big Tech companies have adapted to crises before and emerged even stronger. I don’t know what will happen this time. It’s hard to ignore how entrenched and influential the tech empires are. And it’s difficult to overlook how swarmed they are by doubts and challenges.

Before we go …

• A little Christmas cheer: People are (mostly) receiving deliveries on time ahead of Christmas, my colleague Niraj Chokshi reports. Savvier planning, and more spending, by retailers and delivery companies helped deal with surges in packages. And more people did holiday shopping early and in stores, which eased stress on delivery networks.

• Drones in disaster zones: The Washington Post looks at the pros and cons of small drones that are increasingly used to capture images of natural disasters, fill in for destroyed communications networks or search for people who need help. (A subscription may be required.)

• People care passionately about something on the internet. For five seconds. Fast-moving internet fads — like sea shanties on TikTok — create a snowball effect of attention, says Rebecca Jennings, a writer for Vox. This hyperactivity of trends “makes it much more difficult for people to determine what, if anything, bears actual value.”

Hugs to this

A group of orcas made a rare visit off Rio de Janeiro’s Ipanema Beach.

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Meta, Facebook’s parent company, is aiming for “deep compatibility” with blockchain technology, according to an internal post on Tuesday from a top executive.

In the note to employees, which was obtained by The New York Times, Andrew Bosworth, who will become Meta’s chief technology officer next year, laid out a vision for the social network to adopt and work with various blockchain or cryptocurrency technologies that have collectively become known as web3.

Mr. Bosworth urged caution but said the company should look to adopt the technologies before others, noting that blockchain technology — which are essentially distributed ledger systems — could have “profound impacts on our industry over the next decade.”

“My overall guidance is to target a deep compatibility with the blockchain,” he wrote. “There aren’t many places where I expect us to depend on it exclusively yet, but if we see an opportunity to work jointly with entrepreneurs in the web3 space I expect it will be worth the effort.”

Technologists, entrepreneurs and investors in the tech industry have debated the internet’s future architecture, with some believing that the decentralization offered by blockchain technology is a way to wrest power away from giants including Meta and Google.

But while Google has been reluctant to dive into crypto, Meta has experimented with cryptocurrencies, including an effort to create a global digital currency that could be used by Facebook and WhatsApp users. The head of that crypto project, David Marcus, announced his departure from Meta last month after the digital currency was rebranded and faced scrutiny from regulators.

In his post, Mr. Bosworth, who oversees Meta’s augmented and virtual-reality efforts, said the company should develop ways to work with nonfungible tokens, which are assets verified using blockchain technology, while looking to possibly invest in areas including blockchain-based smart contracts and decentralized autonomous organizations, which are internet-native co-ops governed with cryptocurrency tokens.

Still, he urged Meta’s employees not to overcorrect by only relying on decentralized technologies.

“While most people are happy to use Facebook and Google, some are not,” he wrote. “And those that opt out are disproportionately involved in creating a genuinely impressive wave of technology.”

One of Meta’s board members, Marc Andreessen, who helps lead the venture capital firm Andreessen Horowitz, has created dedicated funds to invest in web3 companies and technologies.

Meta didn’t immediately respond to a request for comment.