Social media have seen the proliferation of misinformation seriously impacting brands and public policies (Di Domenico & Visentin, 2020; Visentin et al., 2019; Marwick, 2018). Combating of fake news and misinformation is a hot theme that will meaningfully shape the future of social media and marketing research, especially in balancing the risks of limited freedom of expression versus the harm of spreading misinformation (Appel et al., 2020).

Social media users are unwilling to fact-check information and tend to avoid information that does not fit their intuition, but scientific literature still lacks in providing convincing explanations of the determinants of sharing misinformation on social media. Against this background, we take the perspective that sharing problematic content is related to the double effort of users to reinforce their identity within their like-minded others and to reinforce their pre-existing beliefs. Based on the contagion approach (Hedström, 1994), we propose that social media users are likely to share previously posted misinformation based on three proximities (symbolic, given by common semantic domains represented common words or expressions; cultural, given by a common set of sources of information; and thematic, given by a common set of hashtags used to disseminate contents).

Our study will contribute to the nascent literature on spreading misinformation on social media and could be of value for companies allowing them to concentrate their marketing efforts on those community that feed problematic contents to stop the proliferation of their brand’s related problematic contents outside the community where it originated.