This study examines how mass shooting narratives emerge on social media through the interaction of platform governance and participatory discourse. Using a two-study design, we first compare moderation policies and enforcement approaches across major platforms, then analyze discourse surrounding five mass shooting events on X as visible outcomes of platform governance. For the two highest-volume events, 24,748 X posts from the Chiefs Parade shooting and 2043 X posts from the Hookah Bar shooting, we employ a retrieval-augmented generation (RAG)-based thematic analysis combining human-guided theme development with embedding-based semantic retrieval. Three lower volume events are examined through human thematic analysis, and 267 Reddit posts from the Chiefs Parade case serve as a qualitative comparative reference. Findings show that users shared breaking news, expressed grief, debated gun violence and media coverage, and interpreted events publicly. Platform governance appears associated with differences in discourse visibility, tone, and persistence.
AreC (2024) ‘Dysfunctional’ appeals and failures of algorithmic justice in Instagram and TikTok content moderation. Information, Communication & Society28(11): 1997–2014. https://doi.org/10.1080/1369118X.2024.2396621
2.
AvidarR (2013) The responsiveness pyramid: Embedding responsiveness and interactivity into public relations theory. Public Relations Review39(5): 440–450. https://doi.org/10.1016/j.pubrev.2013.05.002
CasulaPAnupamAParvinN (2021) “We found no violation!”: Twitter’s violent threats policy and toxicity in online discourse. In: Proceedings of the 10th international conference on communities & technologies-wicked problems in the age of tech, Seattle, WA, 20–25 June, pp.151–159. Association for Computing Machinery.
5.
ChatzakouDKourtellisNBlackburnJ, et al. (2017) Mean birds: Detecting aggression and bullying on Twitter. In: Proceedings of the 2017 ACM on web science conference, Troy, NY, 25–28 June, pp.13–22. Association for Computing Machinery. https://doi.org/10.1145/3091478.3091482
6.
ChandrasekharanEPavalanathanUSrinivasanA, et al. (2017) You can’t stay here: The efficacy of reddit’s 2015 ban examined through hate speech. Proceedings of the ACM on Human-Computer Interaction 1(CSCW): 1–22.
7.
CreswellJWPothCN (2018) Qualitative inquiry and research design: Choosing among five approaches (4th ed.). SAGE Publications.
8.
CroitoruASchuchardRCrooksA, et al. (2020) Responses to mass shooting events. Criminology & Public Policy19(1): 25–51.
9.
DahmenN (2018) Covering mass shootings: Journalistic practices and the problematic role of images. American Behavioral Scientist62(2): 139–158.
DemszkyDGargNVoigtR, et al. (2019) Analyzing polarization in social media: Method and application to tweets on 21 mass shootings. arXiv preprint arXiv:1904.01596.
13.
GaoYXiongYGaoX, et al. (2023) Retrieval-augmented generation for large language models: A survey. arXiv preprint arXiv:2312.109972(1): 32.
14.
GaudetteTScrivensRDaviesG, et al. (2020) Upvoting extremism: Collective identity formation and the extreme right on Reddit. New Media & Society23(12): 3491–3508. https://doi.org/10.1177/1461444820958123
15.
GillespieT (2018) Custodians of the Internet: Platforms, content moderation, and the hidden decisions that shape social media. Yale University Press.
GorwaR (2019) What is platform governance?Information, Communication & Society22(6): 854–871.
18.
GorwaRBinnsRKatzenbachC (2020) Algorithmic content moderation: Technical and political challenges in the automation of platform governance. Big Data & Society7(1): 205395171989794. https://doi.org/10.1177/2053951719897945
JhaverSApplingDSGilbertE, et al. (2019) Did you suspect the post would be removed?” Understanding user reactions to content removals on Reddit. Proceedings of the ACM on Human-Computer Interaction3(CSCW): 1–33.
21.
KambamPThompsonC (2020) The influence of media on mass shootings. Journal of the American Academy of Psychiatry and the Law48(3): 320–329.
22.
KambamPRPoziosVKBondKL, et al. (2020) The influence of media related to mass shootings. Psychiatric Annals50(9): 393–398.
23.
KlonickK (2018) The new governors: The people, rules, and processes governing online speech. Harvard Law Review131(6): 1598–1670.
LankfordATomekS (2018) Mass killings in the United States from 2006 to 2013: Social contagion or random clusters?Suicide and Life-Threatening Behavior48(4): 459–467.
26.
LeeJKanthawalaSBrittB, et al. (2021) Prevalence of anger, engaged in sadness: Engagement in misinformation, correction, and emotional tweets during mass shootings. Online Information Review45(6): 32–48.
LewinK (1947) Frontiers in group dynamics: Concept, method, and reality in social science. Human Relations1(1): 5–41.
30.
LewisPPerezEPiktusA, et al. (2020) Retrieval-augmented generation for knowledge-intensive NLP tasks. arXiv. Available at: https://arxiv.org/abs/2005.11401
31.
LlansóEvan HobokenJLeerssenP, et al. (2020) Artificial Intelligence, Content Moderation, and Freedom of Expression. Center for Democracy and Technology.
32.
LiuDDongZSQiuG (2022) Exploring the contagion effect of social media on mass shootings. Computers & Industrial Engineering172: 108565.
33.
MaaroufAPröllochsNFeuerriegelS (2024) The virality of hate speech on social media. Proceedings of the ACM on Human-Computer Interaction8(CSCW1): 1–22.
34.
McQuailD (2010) McQuail’s Mass Communication Theory. Sage.
35.
MeindlJIvyJ (2017) Mass shootings: The role of the media in promoting generalized imitation. American Journal of Public Health107(3): 368–370.
36.
MurrayJL (2017) Mass media reporting and enabling of mass shootings. Cultural Studies↔ Critical Methodologies17(2): 114–124.
37.
Myers WestS (2018) Censored, suspended, shadowbanned: User interpretations of content moderation on social media platforms. New Media & Society20(11): 4366–4383.
OksanenAHawdonJRäsänenP (2014) Glamorizing rampage online: School shooting fan communities on YouTube. Technology in Society36: 50–59. https://doi.org/10.1016/j.techsoc.2014.08.001
40.
PetersonJDensleyJSpauldingJ, et al. (2023) How mass public shooters use social media: Exploring themes and future directions. Social Media+ Society9(1): 20563051231155101. https://doi.org/10.1177/20563051231155101
41.
PinkSHorstHPostillJ, et al. (2016) Digital Ethnography: Principles and Practice. Sage.
ShoemakerPJVosTP (2014) Media gatekeeping. In: StacksDWSalwanMB (eds) An Integrated Approach to Communication Theory and Research. Routledge, pp.89–103.
51.
SilvaJCapellanJ (2019) The media’s coverage of mass public shootings in America: Fifty years of newsworthiness. International Journal of Comparative and Applied Criminal Justice43(1): 77–97.
SumialaJTikkaM (2011) Imagining globalised fears: School shooting videos and circulation of violence on YouTube. Social Anthropology19(3): 254–267. https://doi.org/10.1111/j.1469-8676.2011.00158.x
56.
SundarSS (1999) Exploring the contingency view of interactivity: Effects of message contingency and modality on user perceptions of interactivity. Journal of Communication49(1): 30–45. https://doi.org/10.1111/j.1460-2466.1999.tb02718.x
57.
SundarSSKalyanaramanSBrownJ (2003) Explicating web site interactivity: Impression formation effects in political campaign sites. Communication Research30(1): 30–59. https://doi.org/10.1177/0093650202239025
ZhangXZhaoKXuW (2017) Tweeting mass shootings: Automated detection and characterization of gun violence incidents on social media. Social Media + Society3(4): 205630511773575.
