More than 100 Reddit communities have banned users from posting links to X in protest at owner Elon Musk’s controversial arm gesture at a rally celebrating Donald Trump’s return to office.

The billionaire twice extended his arm out straight as he thanked the crowd for “making it happen.”

Critics, including some historians, said it was a Nazi salute – Mr Musk has dismissed that, saying comparisons with Hitler were “tired” and “dirty tricks.”

However many Reddit users have been unpersuaded by his response describing his actions as “hateful”, leading the moderators of scores of communities – or subreddits – to stop content being shared on X.

The BBC has approached X and Reddit for comment.

Reddit relies heavily on community moderation, where unpaid individuals known as Redditors decide what is – and isn’t – allowed to be published on their own corner of the website.

They moderate subreddits, the name given to a forum within the Reddit platform which is effectively a community of people who gather to discuss a particular interest.

Since the controversy erupted, dozens of those subreddits have decided they won’t link to content on X, potentially reducing traffic and engagement.

The biggest subreddits to have enforced the ban include basketball community r/NBA, which has 15 million members, female-focused community r/TwoXChromosomes, which has 14 million members, and American football community r/NFL, which has 12 million members.

It is worth remembering that subreddits are almost always run by fans – it does not mean that the NFL or NBA organisations are taking a stance against Musk.

The BBC has independently verified that at least 100 subreddits have banned X posts.

Of this number, more than 60 have at least 100,000 members.

But the actual number that have instituted the ban will likely be significantly higher by taking into account smaller subreddits with only a few thousand members.

And there are many more communities discussing a potential blacklisting.

The subreddits run by fans of football clubs Liverpool, Celtic and Tottenham Hotspur have all instituted the bans, as have communities for many US sports sides as well as Formula 1.

The subreddits where residents of many cities and countries gather around the world – ranging from New Jersey to South Korea – have also blocked posts to X.

And gamers are also amongst those to bring in the ban for video games including Baldur’s Gate 3 and World of Warcraft.

But while the blacklisting may have first started in some of these communities, it is popping up in a variety of places now where people gather to discuss all sorts of topics, ranging from RuPaul’s Drag Race to Disneyland and even the military.

While the vast majority of subreddits discussing a ban are in favour of it, there are some that have refused.

The moderators of the Maine community for example say they won’t institute a ban so long as “the state maintain official accounts there”.

And those running a group for people in British Columbia said they simply aren’t “doing censorship here”.

Though there are many subreddits which already disallow posts from social media, those built around professional sports in particular may have a big impact on referrals to X.

That’s because sports subreddits generally get a lot of content from links to athletes, analysts and journalists who spend a lot of time posting online.

For example, the top two most popular posts of all time on the NBA subreddits are screenshots taken from X, while three of the top ten most popular posts of all time on the AEW wrestling subreddit are screenshots from the platform.

And gaming subreddits have a similar story, with the top posts on the Animal Crossing and Kingdom Hearts communities both screenshots from X.

But that is not to say the bans will necessarily be permanent – Reddit is known for this sort of community movement to protest against wider issues, which doesn’t always work out.

In 2023, thousands of communities “went dark” to contest changes to how the platform was being run.

Some of the biggest Reddit communities then began only allowing photos and videos of comedian John Oliver, following comments from disgruntled users.

But this proved to be short-lived.

Eventually the communities mostly became publicly available again, and Reddit’s plan ultimately proved financially beneficial – the platform subsequently successfully listed on the New York Stock Exchange.