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Communications of the ACM


New Threats to Society from Free-Speech Social Media Platforms

darts projected from a megaphone, illustration

Credit: Jasmina Buinac

The attack on the U.S. Capitol on January 6, 2021 resulted in five deaths, turning it into what some have labeled an unprecedented attack on democracy.10 Recent evidence documented the attack was partially coordinated through free-speech social media platforms (so-called "alt-techs").10 Alt-techs such as Parler, Gab, and Telegram constitute new information, communication, and socialization ecosystems, which lack content moderation, and thus provide a parallel online space for ideas that are outside the boundaries of speech permitted on mainstream platforms. As a result, alt-techs facilitate the circulation of biased, inaccurate, misleading, and conspiratorial content at unprecedented levels and, furthermore, have attracted large numbers of partisan users and extremists. As seen in the example of the attack on the U.S. Capitol and evidence from other violent incidents, the recent emergence of alt-techs might even have dangerous effects on the offline world, including democracies as a whole.

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What Are Alt-Techs?

Alt-techs have emerged as a new social media phenomenon.9 Prominent examples include Parler (, Gab (, 4chan (, 8chan (, Voat (, Gettr (, BitChute (, Telegram (, Discord (, and Mastodon ( These are part of the broader alt-tech ecosystem that provides alternative websites, platforms, and services specifically targeted toward certain, often partisan or fringe, communities. The features of alt-techs are typically not innovative in themselves but rather offer services largely similar in functionality to those found on mainstream platforms (for example, Twitter, Facebook). However, different from mainstream social media, alt-techs self-proclaim as "free-speech" platforms and, because of that, eschew content moderation so users can post content that would not be permitted on mainstream social media.

The reasons for the emergence of alt-techs are many-faceted. In recent years, partisan communities have developed a narrative claiming that speech on mainstream platforms is being "censored" for failure to be "politically correct."11 Such views can be partially attributed to the increasing content moderation efforts from mainstream platforms to limit misinformation, conspiracy theories, and hate speech. For instance, when Twitter and other platforms increased efforts to ban malicious accounts or flag misinformation, many conservative users migrated to Gab and Parler.1,10 Conservative thought leaders also jumped on the bandwagon by endorsing, in particular, Parler as an alternative to mainstream social media.2 Similarly, many liberals, dissatisfied with Elon Musk's new content moderation policy, recently endorsed Mastodon as a Twitter alternative.8 As such, migrating to alt-techs can be seen as a political statement. Overall, a mixture of content restrictions, de-platforming, and bans imposed by Big Tech has contributed to the popularity of alt-techs.

Alt-techs have emerged as a new social media phenomenon.

A particular characteristic of alt-techs is their user base. Especially during the 2020 U.S. presidential election, many alt-techs have witnessed stark growth; for example, Parler counted approximately one million users in June 2020 but more than 13 million only six months later in January 2021.2 The user base of alt-techs tends to be rather homogeneous: a large share of users even self-identify as partisans, extremists, or conspiracy theorists.2,12 Mirroring the user base, the content on alt-techs covers—to a large extent—extreme viewpoints or conspiracy theories. For example, Gab features high levels of hate speech, toxic, and anti-Semitic content.1,9,12 Furthermore, on Parler, hashtags such as #qanon are widespread and posts frequently link to websites known for spreading misinformation (for example, As such, alt-techs form ideologically driven ecosystems where opposing viewpoints are largely absent.8 This can be problematic: Even in mainstream social media, where users are regularly exposed to diverse ideological content, echo chambers of users sharing similar worldviews have led to increased political polarization.5 In the absence of opposing views, alt-techs are likely to accelerate the growth of echo chambers and further benefit polarization and radicalization.8

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Why Alt-Techs Are a Threat to Society

Alt-techs pose direct concerns for society, particularly because they have been frequently associated with violent incidents in the offline world. For instance, the offender in the Buffalo, NY, shooting on May 14, 2022, allegedly shot 10 people in a racist attack inspired by content on 4chan.4 Furthermore, Gab was the main communication channel during the Pittsburgh synagogue shooting on October 27, 2018, a white supremacist terrorist attack that caused 11 people to lose their lives.9 A similar role for alt-techs has been observed for the attack on the U.S. Capitol. Rioters communicated via Parler on how to evade police forces or smuggle weapons into the capitol.10 As such, Parler is often regarded as the primary communication channel of the rioters before and during the Capitol attack.7,10

Alt-techs further provide fertile grounds for misinformation and even disinformation. This includes deliberately deceptive content, with which users seek to spread conspiracy theories, false rumors, hoaxes, and inflammatory opinions to promote their own ideological viewpoints, decrease trust in mainstream institutions, and win followers.6 The proliferation of such content on alt-techs may be partially attributed to their promise of "uncensored" speech. Specifically, the lack of content moderation allows spreaders of misinformation to fill the curiosity gap by sensationalizing "censored" content (that is, "what they don't want you to know"). Another driver that may promote the spread of misinformation is the homogeneity of users. Due to the segregation, confrontation and exchange with other views are rare and thus could remove skepticism that spreaders of misinformation may face on mainstream social media. From a societal perspective, the proliferation of misinformation on alt-techs is alarming as it may undermine the concepts of truth and reality among users, which might directly affect the offline world. For instance, the alleged Buffalo shooter was suspected to be influenced by the "replacement theory," a conspiracy theory claiming a cabal attempts to replace white Americans with non-white people that circulated on 4chan.4

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What We Know about Alt-Techs

Despite imminent concerns, research focusing on a better understanding of alt-techs has remained scarce. One literature stream seeks to generate a better understanding of who uses alt-techs. For example, many users migrated to Parler from Twitter during the 2020 U.S. presidential election,10 and, on top of that, the average user on Parler has strong partisan views.2 Similarly, many users who previously violated Twitter's community guidelines and then migrated to Gab contributed to a more toxic and radical ecosystem.1 Users of alt-techs commonly advocate conspiracy theories.2,12 For example, prior research has shown that users frequently discuss QAnon on Parler, 4chan, and Voat.2,3

A particular characteristic of alt-techs is their user base.

Another literature stream studies what is shared on alt-techs, comparing alt-techs against mainstream social media. For example, content shared on Parler is significantly different from that shared on Twitter, especially before and after the attack on the U. S. Capitol: Many Parler users expressed a less negative sentiment and lower levels of guilt compared to users on Twitter.7 Furthermore, content on alt-techs, such as 4chan, BitChute, and Gab, contains more hate speech than mainstream social media.8 For example, antisemitic hate speech was widely shared on Gab in response to the deadly Pittsburgh synagogue shooting.9 Moreover, websites known for spreading misinformation and partisan content, such as or, are among the most frequently shared links on Parler and Gab.2,12 Overall, this presents increased risks that make users of alt-techs vulnerable to polarization and radicalization compared to mainstream social media.

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The Way Forward

There is an urge for policy-relevant research to better understand alt-techs as newly emerging phenomena. The knowledge available to policymakers often builds upon anecdotal evidence rather than empirical evidence, which may limit assessments that are rigorous, representative, and comprehensive. Due to differences in the user base and content dynamics, earlier findings from mainstream social media might no longer apply.

Interdisciplinary research combining both computational and social science is important to unravel the underlying mechanisms of alt-techs and inform policies to counter emerging threats to society. On the one hand, computational models help social scientists to develop theories describing the mechanism of information diffusion in social networks.

On the other hand, theories from social science help computer scientists by informing the design of computational methods, so that these are effective in capturing the underlying data-generating process (for example, to account for potential confounding, avoid bias, and develop algorithms perceived as trustworthy and fair). Theories from social science can further explain why and where counter-measures such as de-bunking are effective (for example, using theoretical concepts such as social norms, in/out-group members, and so forth). Finally, an interdisciplinary research agenda is essential to establish ethical guidelines for scientists studying sensitive personal information or even individual users of alt-techs.

To address risks emerging from alt-techs, we advocate impactful research along three dimensions: users, content, and society (see the accompanying table). At the user level, more effort is needed to characterize the different groups and identify behavioral factors that promote migration tendencies. At the content level, advanced computational methods, for example, from natural language processing, combined with cross-platform analyses, can provide tools to systematically analyze the proliferation of hate speech, conspiracy theories, and misinformation on alt-techs, as well as their role during specific offline events. At the societal level, there is a demand to evaluate the effect of alt-techs on the segregation, polarization, and radicalization in the offline world, as well as voter behavior and disinformation in war and conflict (for example, coordinated Russian propaganda in the Russia-Ukraine war).

Table. Key research questions to better understand alt-techs.

There is further a need for evidence-based policies that mitigate the risks alt-techs pose to the functioning of modern societies. However, alt-techs have little incentive to adopt stricter content moderation policies as the lack of such policies is the main reason for their popularity. Research such as that discussed here can inform new regulations that enforce alt-techs to establish a level of content moderation that complies with democratic law (rather than putting the power into the hand of private companies). For instance, the Network Enforcement Act (NetzDG) in Germany and the Cyber-security Law in China force platforms to counter misinformation and hate speech by imposing severe penalties for misconduct. In addition, public pressure (for example, from non-governmental organizations and the media) can have a critical impact on the platforms' businesses. As an example, Parler's alleged role in the storming of the U.S. Capitol led to the removal of the Parler app from both the Google Play store and Apple's App store, as well as Amazon stopping to host the website, which ceased Parler from operating for multiple months.

Despite imminent concerns, research focusing on a better understanding of alt-techs has remained scarce.

Regulatory policies and public pressure may help incentivize platforms to foster academic research. For example, in light of the EU Digital Services Act and pressure from U.S. politics, Twitter and Meta launched programs such as the Twitter Transparency Center and the Meta Ad Library to enhance transparency and accessibility of internal data for researchers. We expect that similar efforts will also be effective for alt-techs (for example, Germany's NetzDG compelled Telegram to cooperate with law enforcement agencies, otherwise, the platform risks being banned from app stores). Policymakers can enforce transparency to enable enhanced data access or even mandate platform providers to implement measures for content moderation (for example, counter-speech, fact-checking) and have their effectiveness evaluated through third-party vendors (for example, by researchers conducting large-scale field experiments). Overall, this might contribute to a less radical ecosystem and mitigate the safety risk originating from alt-techs.

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Alt-techs have emerged from niche existence to social media ecosystems that host a large base of partisan users, extremists, and conspiracy theorists. A better understanding of alt-techs is critical as user counts reach new highs and new platforms such as Truth Social ( founded by Donald Trump emerge. Hence, more effort is needed to inform evidence-based policies and other regulations that could mitigate the risks alt-techs pose to society.

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1. Ali, S. et al. Understanding the effect of deplatforming on social networks. In Proceedings of the 13th ACM Web Science Conf. (WebSci 2021).

2. Aliapoulios, M. et al. A large open dataset from the Parler social network. In Proceedings of the International AAAI Conf. on Web and Social Media (ICWSM 2021).

3. Aliapoulios, M. et al. The gospel according to Q: Understanding the QA non conspiracy from the perspective of canonical information. In Proceedings of the 16th Intern. AAAI Conf. on Web and Social Media (ICWSM 2022).

4. Collins, B. The Buffalo supermarket shooting suspect allegedly posted an apparent manifesto repeatedly citing "great replacement" theory. NBC (2022);

5. Finkel, E.J. et al. Political sectarianism in America. Science 370 (2020), 533–536.

6. Freelon, D. et al. False equivalencies: Online activism from left to right. Science 369 (2020), 1197–1201.

7. Jakubik, J. et al. Online emotions during the storming of the U.S. Capitol: Evidence from the social media network parler. In Proceedings of the Intern. AAAI Conf. on Web and Social Media. (ICWSM 2023).

8. Lima, C. and Schaffer, A. Democrats join Twitter alternative Mastodon in protest of Musk. The Washington Post (2022);

9. McIlroy-Young, R. and Anderson, A. From "welcome new gabbers" to the Pittsburgh synagogue shooting: The evolution of Gab. In Proceedings of the 13th Intern. AAAI Conf. on Web and Social Media (ICWSM 2019).

10. Otala, J.M. et al. Political polarization and platform migration. In Proceedings of WWW '21: The Web Conf. (2021).

11. Papasavva, A. et al. Is it a Qoincidence?: An exploratory study of Qanon on Voat. In Proceedings of WWW '21: The Web Conference. (2021).

12. Zannettou, S. et al. What is Gab? A bastion of free speech or an alt-right echo chamber? In Proceedings of The Third Intern. Workshop on Cybersafety, Online Harassment, and Misinformation WWW (2018).

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Dominik Bär ( is a Ph.D. student at LMU Munich and the Munich Center for Machine Learning, Munich, Germany.

Nicolas Pröllochs ( is a professor at JLU Giessen, Giessen, Germany.

Stefan Feuerriegel ( is a professor at LMU Munich and the Munich Center for Machine Learning, Munich, Germany.

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David Tonhofer


In a article about "misinformation" and "disinformation", I read with some astonishment as the first (!) phrase:

> The attack on the U.S. Capitol on January 6, 2021 resulted in five deaths, turning it into what some have labeled an unprecedented attack on democracy.

While the second part of the sentence is definitely true and the people responsible for such outrageous hyperbole should be held to proper account, the "five deaths" mentioned are, I am happy to reveal, just rank disinformation.

Let's turn to the NYT ("These Are the People Who Died in Connection With the Capitol Riot"), frankly a shadow of its former self of 20 years ago or so, and nowadays a rank partisan outlet, but sufficient for our means. I will paraphrase and shorten and give you the following list:

- Ashli Babbitt, an Air Force veteran, killed by an (unidentified) Capitol Police officer (gunshot wound to the neck from 2m away).
- Kevin D. Greeson, died of a heart attack.
- Rosanne Boyland, crushed in a stampede then died of an overdose, allegedly.
- Benjamin Philips, died of a stroke.
And in the days and weeks after the riot:
- Officer Brian D. Sicknick of the Capitol Police died (of natural causes as far as we know)
- Officer Jeffrey Smith of the Metropolitan Police Department, committed suicide
- Officer Howard S. Liebengood of the Capitol Police, committed suicide

We thus conclude that

> The attack on the U.S. Capitol on January 6, 2021 resulted in 1 violent death among the protestors at the hand of Capitol Police.

I do hope the authors will take the time to submit a correction to lessen the cognitive dissonance currently existing between the subject and the opening phrase.

With best regards,

-- David Tonhofer

Russ White

This article needs a lot of corrections, such as calling what happened on January 6th an "insurrection," and implying the five people who died were all somehow government actors killed in the process of this "insurrection." This is a rather dishonest framing.

Further, I note that all the "alt tech" sites mentioned are perceived to be "right wing." The authors could add a lot more balance by mentioning some of the left-wing alt-tech sites, and not implying the definition of "misinformation" is "anything a government authority does not approve of." In fact, the entire point of free speech is to counter the "official narrative" with other views and opinions, often backed up by facts not reported elsewhere.

For instance, in the case of a local train derailment the "official story" might be that no harmful substances were spilled. People who live in the area, however, might know about specific incidents that counter or discredit the official narrative. In the view of "misinformation" accepted in the article, the local reporters are "radical" and "dangerous," and should (rightly) be removed from any access to a broader audience.

This is all counter to the purposes of free speech, and counter to the founding ideals of the technology world.

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