Twitter starts marking Substack links with a warning stating the link “has been identified by Twitter or our partners as being potentially spammy or unsafe”
I can neither confirm nor deny :) — However, this month I'll explore how to fill a complaint with @EU_Commission in terms of anticompetitive practice. … Bill Barol / @billbarol@journa.host : I would like to get Substack Notes, and I would like it to have massive uptake from all the funny people I used to follow at Twitter, like, immediately please. I kinda need this thing to work. Rob Pegoraro / @robpegoraro@journa.host : What you see on the birdsite when you try to retweet Substack's subtweet of the control-freak regime running Twitter into the ground... and what a fucking pathetic display of fragility it is to block people from retweeting or liking such a generic statement of principles. Tweets: Seth Abramson / @sethabramson : Elon's pettiness is boundless. Searching Twitter for the word “substack” now returns search results for the word “newsletter.” Elon is as big an asshole as I've ever come across in my life. And I'm a Trump biographer. https://twitter.com/... Judd Legum / @juddlegum : Twitter now warning users that links to Substack may be “unsafe” https://twitter.com/... Eric Newcomer / @ericnewcomer : Substack CEO Chris Best responds to @elonmusk https://twitter.com/... @0xabad1dea : “Substack isn't blocked but also they're blocked because they were downloading our database to set up a twitter clone, which is both a technical action and a business plan that makes perfect sense to me” Tim Culpan / @tculpan : It looks like @elonmusk sees @SubstackInc as a legitimate threat to @Twitter At first it looked like a mere placeholder, as I wrote in December, but with new features the threat from Substack is real https://www.bloomberg.com/... https://twitter.com/... @normative : Elon: “I'm going to make fighting spam on Twitter a priority.” Also Elon: “Let's train our users to disregard security warnings by flagging whatever competitor I'm wetting myself about this week.” Zeynep Tufekci / @zeynep : For real. Searching for the word substack on Twitter returns “newsletter”.🤪 What's next to be hardcoded? Search for Elon returns “the most amazing funniest guy ever”? 🤷♀️ https://twitter.com/... https://twitter.com/... Jason Aten / @jasonaten : trying this again (last time I linked the substack domain): The link block doesn't seem to affect Substacks that use custom domains. It's literally just blocking subdomains dot substack dot com. absurdly, you can't even reply to tweets that quote tweet those subdomains. Angus Davis / @angusdav : What @elonmusk & @Twitter are doing to Substack is wrong & short-sighted. Many draft off the platform, but breaking links by inserting BS “unsafe” warnings is wrong. Old regime blocked links to @nypost, which was wrong too. Twitter is like a common carrier, should act accordingly Matt Stoller / @matthewstoller : I turned my Substack link into a tinyurl, and Twitter is now saying it's malware or dangerous. Love the deceptive practice! https://twitter.com/... Dan Primack / @danprimack : I always figured that Elon's free speech absolutism would have its limits. Just didn't realize that the limit would be posting links to a startup worth less than 2% of what he paid for Twitter. Greg Isenberg / @gregisenberg : If you click the link in my bio, this is what you'll see Twitter and Elon Musk really don't want you to go to Substack... https://twitter.com/... Lyle Enright / @ynysdyn : So apparently Twitter doesn't block Substack anymore, it only warns you that you might get an STI. Classy. So, so classy. https://twitter.com/... Dan Primack / @danprimack : Was curious so went to @pmarca account. Then clicked on bio link to his Substack. This is what popped up, and I've replicated it elsewhere. If Elon wants to fight with Substack and kill embeds, his perrogative. But this is straight up lying. Twitter knows the link isn't “unsafe” https://twitter.com/... Terry Van Loon / @terrybythebay : @TitterDaily At the very least REMOVE this despicable “warning” on the Substack link. Who are the cowards at Twitter afraid of a little competition? https://twitter.com/... Matthew Yglesias / @mattyglesias : Not sure what future this platform holds for me. Subscribe to Slow Boring (even just the free tier) and you'll be able to read my shortform Notes when it comes out of beta next week. https://www.slowboring.com/... @katiemcvay : somewhere bari weiss is mysteriously dried eyed, despite the threat to her precious ~*~FrEe SpEeCh~*~ that is this twitter warning when you click a substack link https://twitter.com/... @ettingermentum : on substack: I get paid actual money to post, don't need to see Elon Musk all the time on Twitter: no money, Elon Musk everywhere Hmmmmmm... @harrymccracken : That's enough. https://www.theverge.com/... Brady Dale / @bradydale : This is such garbage I am actually thinking it will tip me over into deleting my account. It would really screw up my work but... IDK man It's just so stupid Eddie Du / @edourdoo : This notice seems instead to be Twitter's latest hostile move toward Substack after the email newsletter platform announced its own Twitter-like “Notes” feature on Wednesday. https://www.theverge.com/... See also Mediagazer
Context & Ripple Effects
Twitter’s treatment of Substack links arrived as Substack was introducing Notes, prompting users to frame the warning as a possible competitive response. Substack’s founders publicly cast the change as evidence for publisher-controlled distribution in their response to Twitter’s abrupt restriction.
The episode sits within a broader pattern of Twitter/X tightening control over how people access and share content: later coverage documented web browsing behind a sign-in wall and reduced article-link previews. Together, those actions make the platform’s interface rules more consequential for outside publishers.
First-order effects
- Twitter users encounter a safety/spam interstitial when opening Substack URLs, adding friction and reputational risk to sharing and reading Substack publications.
- Substack and its writers lose a previously straightforward distribution path on Twitter just as Notes is positioned as a social-reading alternative.
Second-order effects
- Publishers and creators dependent on Twitter referrals have reason to diversify audience acquisition and emphasize channels they control, rather than assume link reach is platform-neutral.
- The warning sharpens the competitive stakes between Twitter and Notes: a rival social product must acquire users while its links face added friction on the incumbent network.
Third-order effects
- If platforms increasingly apply safety labels, login requirements, or preview changes to external destinations, link distribution becomes a strategic gatekeeping lever rather than a neutral utility.
- The durable tension is between legitimate abuse controls and opaque enforcement that can advantage a platform’s own adjacent products; credibility depends on clear, consistently applied standards.
The trend: This is one data point in the shift from open social referral toward platform-controlled access and presentation of third-party content.