Blood services worldwide continue to face persistent challenges in recruiting and retaining voluntary, non-remunerated blood donors, particularly among younger populations. Over the past decade, communication strategies have shifted from traditional mass media to digital environments, where social media platforms, influencers, and online communities increasingly shape social norms, identity formation, and prosocial behaviour. These digital tools are now widely used to mobilise blood donors; however, the existing evidence base remains fragmented across disciplines, regions, and study designs.

This scoping review aims to map and synthesise the available evidence on the role of social media, influencers, and online communities in blood donor recruitment and retention. It further seeks to identify key mechanisms underlying digital engagement, highlight knowledge gaps, and propose a digital sociology-informed framework to guide “next-generation” donor engagement strategies.

A scoping review was conducted in accordance with PRISMA-ScR guidance. Major databases (PubMed, Scopus, Web of Science, PsycINFO, and CINAHL) and relevant grey literature were searched for publications from 2010 to March 2025. Eligible studies included empirical research and reviews examining (i) social media platforms, (ii) influencers, celebrities, or digital opinion leaders, and/or (iii) online communities or mobile and social applications used for blood donor recruitment or retention. Data were charted on study design, setting, digital platform, target population, intervention characteristics, and donor-related outcomes, and synthesised narratively. Evidence from broader eHealth and communication-intervention reviews was incorporated to contextualise social media within wider digital donor ecosystems.

The body of evidence has expanded rapidly but remains methodologically and conceptually heterogeneous. Facebook's blood donation tools and associated engagement strategies were associated with modest yet consistent increases in total donations (approximately 4%) and first-time donations (around 19%) in multi-country quasi-experimental studies. Platforms such as WhatsApp, Twitter/X, and Instagram function primarily as “just-in-time” mobilisation channels, particularly in the Middle East and low- and middle-income countries, with high success in meeting urgent donation requests but limited longitudinal data on donor retention. Systematic reviews of eHealth interventions and mobile applications suggest that digital tools, including apps, SMS, and social media, can improve donation and repeat behaviour when interventions are personalised, interactive, and integrated into service workflows. Emerging literature highlights donors as digital advocates and explores how online communities foster donor identity, peer norms, and advocacy. In contrast, influencer-driven campaigns are largely documented in grey literature, and concerns persist regarding commercialisation, fear-based messaging, and misinformation.

Social media and online communities have become central infrastructures for donor discovery, persuasion, and relationship-building, particularly among younger populations. However, the current evidence base is skewed toward high-income settings, single-platform interventions, and short-term outcomes. Future research should adopt theory-driven approaches, address equity and ethical concerns, and evaluate integrated, multi-platform strategies that link influencers, micro-communities, and formal blood services within coherent digital donor ecosystems.