The Athletic, the venture-capital funded online sports media start-up, was flagging Reddit posts that included the site’s content, all of which is exclusively available to paid subscribers and protected behind one of the journalism industry’s stiffest paywalls, and the social media platform was then removing those posts from the site.

Since then, the hockey subreddit changed its rules to allow users to post links whose content is protected by a paywall, “but circumventing the paywall in the comments or any other means by posting the article in any form will result in a ban.”

With free sports coverage widely available on the internet, the Athletic employs stringent safeguards over who can access its content. It’s a strategy that’s led the Athletic to develop a growing and loyal audience — the company is approaching 1 million subscribers, representatives told The Post — but it could cost the publisher traction on social media and on Reddit, where sports media sites compete for an audience.

Indeed, fan communities on Reddit have begun removing links to and excerpts from Athletic articles, with moderators wary of the platform striking posts due to copyright concerns.

Moderators of the Buffalo Sabres subreddit will remove “links or copy/pasted text of paid subscription material,” according to the channel’s rules. The site’s main baseball subreddit, with 1.3 million members, forbids users from providing “access to content behind a paywall in any way, including re-hosting content on other sites or posting content in text posts/comments.”

The Chicago Bulls subreddit banned content from the Athletic in December. The fan group for Liverpool FC, which includes more than 235,000 members, did the same in February.

“We rewrote one of the rules with the Athletic in mind,” Bulls subreddit moderator Andrew Aubert said in a phone interview. “They’re the only publication we’ve had causing issues. There hasn’t been a lot of two-way dialogue between us and them. We’ve spoken with the Chicago Sun-Times and other publications, but we haven’t heard from [the Athletic]. We have an open invitation to them to start that dialogue to see what they’d want.”

“Recently The Athletic has taken a harder line on copyright infringement — with them contacting Reddit, who contacted a subscriber that used to post article summaries in comments,” a Liverpool moderator posted. “As such, posting about The Athletic articles now becomes purely subscription farming, as the contents are only visible to paying subscribers. It also puts the sub and posters at risk. We’ve really got no choice at this point than to ban them as a source.”

The Athletic files requests with Reddit under the 1998 Digital Millennium Copyright Act to remove content that violates intellectual property regulations, Taylor Patterson, the Athletic’s senior communications director, said in an interview.

Reddit has an online form that allows users to flag posts that constitute copyright infringement.

Athletic readers who are also Reddit users often refer problematic posts to the Athletic, Patterson said, along with the company’s journalists, who frequently use subreddits to follow social media conversations about the teams they cover.

“When it comes to our content — and I’d imagine that we’re not the only publication that views activity on Reddit this way — our content is behind a paywall and we want to be sure that we’re preserving that model” she said. “When our content is posted in full, it’s violating the fundamental way that the business thrives here.”

Aubert said the Athletic monitors Reddit posts more aggressively than other media companies. The Bulls subreddit moderators are sympathetic, Aubert said, to the Athletic protecting its paywall model and proprietary reporting.

But users are unclear, he said, where the publication and Reddit administrators draw the line on what constitutes a copyright violation. Can users, for example, post a provocative quote included in an Athletic story and offer their opinion? Can they summarize the contents of an article? Can they copy and paste a paragraph or two to admire a reporter’s nifty writing?

“That’s the question,” Aubert said. “How much is enough to have a healthy discussion without encroaching on the copyright of the Athletic? We decided to simplify things where it’s all or nothing.”

A Reddit spokesperson said the site has no firm threshold over what constitutes copyright infringement. Patterson said the Athletic doesn’t have one, either.

That’s left moderators to fend for themselves while trying to stay on the right side of Reddit’s rules and the Athletic’s judgment. It also has moderators fielding complaints from some users who say they can’t participate in certain conversations on Reddit, which is free, because they choose not to pay for an Athletic subscription.

“You have this kind of open forum where everyone is supposed to be able to converse, but then inside that you have these smaller walled gardens where only 10% or so of the sub can see the Athletic articles,” Aubert said. “That didn’t seem very just to us to act as this de facto advertising platform for the Athletic.”

Patterson said Reddit users who don’t subscribe to the Athletic can still interact with reporters through periodic digital question-and-answer sessions on Reddit. The Athletic also has its own comments section beneath each article.