If Reddit went offline tomorrow, you would see immediate ripples across the Internet.

First, and perhaps least importantly, traffic to porn sites would plummet.

Later, major news, entertainment and e-commerce sites, including YouTube and Amazon, would feel a notable, if not debilitating, hit.

And then, concur a dozen Reddit power-users, academics and social media experts interviewed by The Post … life would go on as normal across the Internet.

To be clear, no one actually expects the Internet’s “front page,” and its 35th most popular Web site, to shut down — not now, anyway. But in the wake of Reddit’s latest and most traumatic bout of internal drama, several pundits have found themselves pondering the hypothetical worst case: one in which the tensions between Reddit’s leadership and its user base topple the site, entirely.

“If Reddit suddenly disappeared off the Internet, it would change the Internet,” decreed Jeffrey Eberhard, one of the site’s most popular users.

The question is: How would the Internet change? And what, just as pressingly, does it stand to lose?

Meet the sites that depend on Reddit

To understand what the Internet would look like without Reddit, you first have to understand what Reddit does for the Internet now. On one hand, it’s an aggregator of news, ephemera and information: a viral meritocracy through which the best stuff on the Web wends its way up and out.

The site is composed of a system of smaller, interest-based forums, called subreddits; users submit links and text posts to these forums, then vote them up or down to determine placement.

Reddit’s front page — the best of the best forums, essentially — earns something like 140 million page views every week. As such, Reddit has the extraordinary power to throttle page views to other Web sites, crown Internet celebrities, and invent brand-new Web trends and memes.

That issue — the raw, numerical traffic issue — would be the Internet’s first pain point, if Reddit should shut down. According to Similar Web, a leading traffic analytics site, Reddit supports a downstream network of other news, entertainment and e-commerce sites, which would face significant traffic and, potentially, revenue losses without it: Imgur, Reddit’s de facto image host, derives more than half of its traffic from Reddit, for instance; adult sites such as Pornhub and Xvideos also tend to depend on it for a large share of their traffic.

“You would be surprised,” Pornhub’s vice president said in a telling Reddit AMA. “We get millions of social traffic visits a month.”

Reddit’s aggregate effect on most other sites is minimal: It refers millions of readers to YouTube, Wikipedia and Twitter, the data suggests, as well as to the Guardian, The Washington Post, the New York Times and a long string of other legacy news outlets. But these places receive the vast majority of their Web traffic from somewhere else, explained Liam Corcoran, the head of communications for the social analytics firm NewsWhip, and Reddit “spikes” are so capricious that they don’t count or plan on them.

The Post, for instance, is the second-most popular news outlet on Reddit, which makes it a pretty good bellwether for how other media outlets would be affected by changes to the site. The Post’s traffic from Reddit is negligible, though, in comparison to referrers such as Facebook, Twitter and Google; my colleagues on the audience team would surely miss that traffic should it dry up, but they wouldn’t stay awake mourning it.

But where will the memes come from?

But forget, for a second, everything you’ve heard about Reddit, the “news aggregator” and traffic kingmaker. Beneath the big headlines, the Bad Luck Brians and the blockbuster AMAs, there’s a vast catacomb of more than 8,700 interest-based forums — what communications researcher Kelly Bergstrom calls “affinity groups.”

Reddit’s affinity groups are legion. There are groups for pug-owners; groups for Bostonians; groups for people who like cricket, want relationship advice or straight up need help. These networked pockets serve something of a dual role: primarily as social and support groups for the 3.7 million people who belong to them, and secondarily as incubators for ideas, jokes, would-be viral stories, and Internet culture as a whole.

And while it’s become something of a cliche, in recent years, to accuse the media of pilfering the best material from these communities, there’s plenty of evidence that that does, in fact, happen: A recent Priceonomics analysis of Buzzfeed stories found that Reddit and Imgur accounted for about 5 percent of all the site’s sources.

“For the rest of the Internet, Reddit is a much-needed filter,” said Max Patrick Schlienger, another high-power Reddit user. “Top-scoring submissions make their way out into the greater Internet, finding new life on news Web sites, Facebook walls, clickbait sites, Twitter feeds … the list goes on .”

… and on, and on. Redditors say it’s not just top posts that leak off Reddit and into mainstream society: It’s the squishier, less measurable bits of skill and knowledge and nuance gleaned and transferred outward by the millions of individuals in the community. How to build humane mouse traps. What book to read next. Why you should or shouldn’t revisit things with your latest ex.

“I’ve gotten countless messages [about] how people have been made so much happier, or even stopped killing themselves, from my posts or subreddits,” said one super-user who moderates a number of the top advice communities on Reddit.

In some ways, of course, these are benefits that can also be credited to the entire Internet, which is — if not a series of tubes — certainly a blinding array of affinity groups. Since Reddit was founded in 2005, mass social networks such as Facebook (b. 2004), YouTube (2005), Twitter (2006) and Tumblr (2007) have grown exponentially. All four serve as conduits for this very type of communal knowledge- and social-sharing.

While Reddit may be unique in its variety, in other words, it’s not the only show in town. And that has never been truer for Reddit, alas, than it is right now.

According to Similar Web, traffic to Panjury — a two-year-old ranking site that, rather like Reddit, “lets you opinionize everything” — spiked 500 percent since Reddit’s latest pains. Voat.co, the Reddit clone that has copied its predecessor so exactly that it refuses to acknowledge it by name, has also seen visitors rocket into the millions in the past week.

Perhaps most ironically, the original Reddit is enjoying a nice rebound at Reddit’s expense: Since July 4, Digg’s daily traffic has jumped 47 percent.

The fall of Digg, all over again

There is a certain, self-obliterating nihilism inherent in all Internet things. Nothing is worth celebrating, or discussing, or holding to the light, because it’s all replaceable and fleeting: just code that can be rewritten, on sites that can come down, on servers that sit in cool, airless rooms underground.

Digg — once an Internet and venture capital darling — justifies that cynicism pretty well: For years the front-runner in the crowd-sourced news-aggregation space, light years ahead of Reddit and its ragtag team of geeks, Digg defined the Web for a certain generation of users. (“Digg was a way of life,” one of them enthused in 2013.)

Then it cracked down on piracy in a controversial case and forced out a redesign nobody liked. In 2010, critics began floating the “also-ran,” Reddit, as a good alternative. By 2012, when the original Digg was sold for parts, Reddit’s traffic had more than quadrupled — and outside a small group of hangers-on, the Digg “way of life” wasn’t much missed.

Ironically, as that baton was passed, Reddit co-founder Alexis Ohanian wrote a snarky open letter to Digg’s Kevin Rose: Users would flee the site, he claimed, because of corporate meddling by investors. No community, even a great one, could survive that kind of divergence between its leadership and user base. Even Digg, he implied — the almighty Digg — could definitively be replaced.

Now the virtual circle of life trundles onward — poised, it would seem, to grind Reddit down, too. In certain lights, in fact, it doesn’t matter how profoundly huge or popular or resilient the site still is, or how theoretical its consequences would be. History suggests that all sites eventually fade from relevance, aging and waning at breakneck Internet speed.

Look at Geocities or Friendster or Myspace or Digg. The Internet adapts; we get over it.

“The world would move on,” sums Schlienger, who goes by the Reddit username RamsesThePigeon. Since joining Reddit in 2011, he’s expended more than 100,000 words there — 100,000 words that would disappear, like that, should Reddit ever end.

“For a little while, though,” he added, “the Internet would be a less enjoyable place. And in our modern-day world … that might as well be the apocalypse.”

Liked that? Try these!