I completely turn my phone off when I go to the movies. Not just on silent – all the way off. I say this not because I think that I’m better than you, or that by doing so the ghost of Billy Wilder will come back to shake my hand. I consider it one of life’s little luxuries: for at least an hour and 45 minutes, I am entirely unreachable. I keep my phone off for the duration of the credits, too. It feels decadent to stay put as my fellow moviegoers slowly filter out, illuminated only by rolling text.

And, lately, the glow of the Letterboxd app.

Over 26 million people use Letterboxd, a movie-cataloguing app. Like the Criterion Collection or A24, it has become industry shorthand for a certain type of tastemaker who hypes new releases and delights in rediscovering old classics. Users rate and review movies, and the funniest or most illuminating critiques rise to the top of the page, incentivizing cinephiles to put in some effort.

On a recent trip to the movies, the credits had barely started before the man in front of me began typing his review. A few seats over, a couple sat, heads down, jotting down their respective thoughts.

The late film-maker David Lynch had a piece of advice: write down every great idea the exact moment that it comes. If you don’t, it could slip your mind, and, as he put it: “If you forget a good idea, you want to commit suicide.” Lynch was speaking to aspiring film-makers, but the same ethos applies to Letterboxd.

Josh Stern, a 20-year-old student in New York, always writes his reviews from his movie seat.

“If I don’t get my thoughts out quickly once the movie ends, my reviews are much less coherent and articulate,” he said. “It takes some time. I’m pretty slow, and my girlfriend doesn’t like it.”

Stern goes to the movies a lot – 182 times last year – and is on a first-name basis with the theater employees, who sometimes have to kick him out so they can start cleaning the aisles. He thinks it’s fair game to milk the credits: “When you pay for a movie ticket, credits are a part of the movie.”

Letterboxd’s most enthusiastic supporters credit the app with reviving excitement around a battered film industry, where productions are down and unemployment is up. (Letterboxd also boasts the kind of demographics brands covet – its highest cohort of users is between the ages of 18 and 24, followed by 25 to 35.)

Hype begets hype; eagerly awaited movies see a flurry of activity on Letterboxd immediately after the first screenings. The most-liked review of Emerald Fennell’s divisive Wuthering Heights – “emily brontë died of tuberculosis 177 years ago yet this adaptation is still the worst thing that has ever happened to her” – has more thank 50,000 double taps. The Moment, Charli xcx’s fictionalized retelling of Brat summer, produced this comparison to tabloid enemy Taylor Swift’s concert film: “eras tour documentary found dead.”

“It’s a little bit of an addiction,” said Ben Glidden, a 33-year-old New Yorker who works in marketing for women’s sports. He also likes to write reviews during the credits. “Reflecting on what you just saw, immediately after you saw it, helps with the artistic experience. It helps you grasp the key messages of a film. If it makes you feel like a warm hug, that’s not necessarily something you remember five hours down the line.”

Glidden feels most compelled to review a film if it was very good – or very bad. Case in point: he recently sat through the Chris Pratt sci-fi vehicle Mercy. “I was actually so offended by how egregiously bad it was, that I was excited to pull out my phone and give it a half-star review,” he said. (Glidden’s a tougher critic than the Guardian’s film critic Pete Bradshaw, who gave the film three stars, calling it, “ingenious and watchable stuff”.)

Dakota Chester, a 28-year-old New Yorker who works in social media, saw Arco, the Oscar-nominated animated fantasy film, at an Upper West Side theater and stuck around to write the review (“it got five stars”). He’s clocked worse behavior: people taking out their phones to Letterboxd the movie they are currently watching. “That gets on my nerves,” he said.

One of film’s most enduring urban legends recounts a screening of the Lumiere brothers’ 1896 silent short that showed a train pulling into a station. Cinema was in its infancy and – according to this debunked rumor – the shot of a locomotive heading straight toward the camera shocked the crowd so much that people ran away screaming.

A hundred-and-thirty years later, cinema etiquette remains just as bad. No one knows how to act in public any more, especially when the lights go down: viewers take pictures of the screen, bring in smelly food, and, as was the case during Barbenheimer summer, sometimes engage in all-out brawls.

Some have taken to social media to debate the appropriateness of Letterboxding during credits. When one TikTok user posted about her “quiet little moment” writing a review in an AMC theater after the credits ended, movie theater employees chimed in. “Pls do this in your car, as soon as the credits stop rolling we have to clean in there or we get way behind in our scheduled cleans,” one wrote. “Take this to the lobby,” another added.

Courtney Mayhew, a representative for Letterboxd, wrote in a statement: “Anecdotally, we’ve heard from members who’ve struck up conversations after noticing someone nearby on the app, sometimes leading to ongoing friendships or just a great chat about what they’ve just watched. That impulse to get your thoughts down while they’re fresh is something we understand – it’s part of the ritual for many people … And obviously, phones out during the actual film is still a cardinal sin – we’re not monsters.”

Other Letterboxd users like to let a film marinate before posting. Irene Vasquez is a 22-year-old film student who joined Letterboxd in 2018 and credits the app for helping her take movies more seriously.

“As I’ve seen it get more popular, it’s gamified movies for people, and it feels like everyone’s in competition to watch as many movies as possible,” she said. “I get frustrated with all the people who pull out their phones immediately to rate films, because I really value sitting with a movie and letting it sink in. I treasure that experience.”

Professional critics used to be arbiters of taste, but in a fractured, post-Gene Siskel or Pauline Kael media ecosystem, Letterboxd reviews probably do more to get young people talking to each other about films than any New York Times writeup could. Raphael Martinez, 43, who manages and programs for a movie theater in Chicago that caters to a “pretty hardcore” art-house crowd, is heartened by the app’s most immediate reviewers. “Within 20 minutes of the movie ending, we have a handful of advertisements on Letterboxd for the movie,” he said. “It helps get people to the theater and gauges community reaction to what we show.”

In the 2010s, Marvel movies conditioned millennials to stay for post-credit scenes offering breadcrumbs or plot reveals for future films in the universe. Martinez found that much more annoying than the cinephiles who stay to get their thoughts down. “People weren’t doing anything, they would just wait around,” he said. “Now, people are hanging out, engaging, and it’s more of a vibe, as opposed to simply consuming.”