Electronic Word of Mouth: A Systematic Review of Its Evolution, Theoretical Foundations, Dimensions, and Role in Contemporary Consumer Marketing
DOI:
https://doi.org/10.31305/rrijm.2026.v11.n08.020Keywords:
electronic word of mouth, eWOM, online reviews, influencer marketing, source credibility, information adoption, consumer decision making, systematic literature reviewAbstract
Electronic word of mouth (eWOM) has grown from a peripheral curiosity in early internet marketing research into one of the most extensively studied constructs in consumer behaviour, spanning marketing, information systems, and communication scholarship. This paper synthesises close to three decades of eWOM scholarship, tracing its conceptual origins in offline word of mouth theory, mapping the principal theoretical lenses through which it has been studied, and reviewing empirical findings on its constituent dimensions, its major platforms, and its documented effects on consumer decision making. Particular attention is given to the granular dimensions of eWOM, including valence, volume, argument quality, source characteristics, and receiver characteristics, each of which has generated its own distinct empirical literature. The review then turns to the rise of influencer-driven eWOM and the conceptual difficulty it poses for definitions of word of mouth that assume a non-commercial source, a development with direct relevance to product categories carrying high identity and appearance salience, such as personal care and beauty. The review identifies persistent gaps in the literature, including limited category-specific research, inconsistent operationalisation of eWOM credibility, and underexamined generational variation in eWOM processing.
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