eWOM and content marketing strategies: maximizing brand engagement among social media users in Spain

This study analyses how brands' content marketing strategies on social networks influence electronic word of mouth (eWOM), a major predictor of business success that reflects consumer engagement and shapes behaviours such as increased purchase intention, willingness to pay more, reduced perceived risk, and strengthened brand trust and loyalty. While prior research has focused on isolated aspects of digital communication, such as message format or content appeal, this work incorporates additional key elements—brand humanization, personalization, and conversational relationships—that are essential for fostering trust and engagement in today's audiovisual content on platforms like Instagram and TikTok. Grounded in theories such as Service-Dominant Logic, brand personalization and humanization, Uses and Gratifications, trust transfer, Marketing Communications Theory, and Media Richness Theory, this research proposes a conceptual model based on the stimulus-organism-response (SOR) framework. The study analyses 250 Instagram posts and 250 TikTok posts from top-interaction consumer brands in Spain, measuring independent variables such as brand consistency, post position, message format, celebrity endorsement, content attractiveness, and interactivity, with eWOM operationalised as the volume of likes and comments. Control variables included posting day, emoji use, and post length, with content analysis applied for coding and negative binomial regression for hypothesis testing. Findings reveal platform-specific patterns: while message format drives eWOM on TikTok, content attractiveness is more influential on Instagram. Celebrity endorsement is the only variable showing similar effects across platforms, increasing likes on both networks and comments on TikTok. This work addresses the gap in comparative analyses of content effectiveness between platforms with distinct social and technical dynamics, offering evidence-based insights for optimising brand communication strategies according to platform-specific audience interaction styles, message temporality, and visual engagement.