In This Article Expand or collapse the "in this article" section Electronic Word-of-Mouth (eWOM)

  • Introduction
  • The Role of eWOM in Advertising, Communication, and Marketing
  • Special Journal Issues on eWOM
  • Overview Articles
  • Social Media–Based eWOM and Purchase Intentions
  • The Role of Influencers
  • Corporate Reputation and Corporate Social Responsibility (CSR)
  • Cross-Cultural Differences in eWOM

Communication Electronic Word-of-Mouth (eWOM)
Shu-Chuan Chu
  • LAST REVIEWED: 22 September 2021
  • LAST MODIFIED: 22 September 2021
  • DOI: 10.1093/obo/9780199756841-0267


The concept of electronic word-of-mouth (eWOM) was introduced in the mid-1990s, when the Internet was beginning to change the ways consumers interacted with each other. eWOM can be generally defined as consumers’ information sharing and exchange about a product or company via the Internet, social media, and mobile communication. eWOM has been recognized to lead to high retransmission intentions because it is easy for consumers to generate conversations online. It also allows information to be passed along globally and quickly. Because of the impact of eWOM on consumer behavior, academic research on eWOM has been documented in disciplines such as advertising, marketing, communication, management, and electronic commerce. Over the past few decades, research has demonstrated the impact of eWOM on sales, product evaluations, purchase decisions, customer satisfaction and loyalty, and consumer-brand relationships. Research has also examined antecedents and motives of eWOM. Factors such as consumers’ desire for social interaction, desire for economic incentives, concern for other consumers, and the potential approval utility have been identified as important motives that drive consumers’ eWOM behavior. In addition, individuals’ social relationship factors (e.g., social capital), as well as message source and characteristics, are antecedents that lead to eWOM behavior. In this article, eWOM is considered in many different formats, such as product review sites, emails, discussion boards, user-generated content, social media, and online communities. This article begins with citations concerning the Role of eWOM in Advertising, Communication, and Marketing. Next, Special Journal Issues on eWOM and Overview Articles are presented. Finally, key research areas are highlighted: Social Media–Based eWOM and Purchase Intentions; the Role of Influencers as a new source of eWOM; the impact of eWOM on Corporate Reputation and Corporate Social Responsibility (CSR); and Cross-Cultural Differences in eWOM. These areas together explain the antecedents and consequences of eWOM.

The Role of eWOM in Advertising, Communication, and Marketing

Electronic word-of-mouth can be conceptually defined as “any positive or negative statement made by potential, actual, or former customers about a product or company, which is made available to a multitude of people and institutions via the Internet” (Hennig-Thurau, et al. 2004, 39). Thus, eWOM occurs when consumers exchange information online, and it can be observed in various forms, such as user-generated content, online product reviews, personal emails, and social media posts. As digital media and new technologies continue to evolve, eWOM has been identified as an important topic in advertising, communication, and marketing research. In today’s cluttered world, eWOM is considered to be more influential than advertising and marketing messages. Because eWOM disseminated through friends and family is perceived as more trustworthy and credible than advertising by marketers, generating positive eWOM communications has been recognized as an important promotional tool. The seminal work Hennig-Thurau, et al. 2004 provides a definition of eWOM and examines consumers’ motivations of participation in eWOM in consumer-opinion platforms. Chevalier and Mayzlin 2006; Maslowska, et al. 2017; and Roy, et al. 2019 concentrate on the role of eWOM in sales and purchase behavior, while Dellarocas 2003 and Fulgoni and Lipsman 2015 offer insights on how digital WOM is different from traditional offline WOM. Dwyer 2007 examines the impact of eWOM on consumer communities. Phelps, et al. 2004 investigates consumers’ motivations to pass along email, and Okazaki 2009 expands PC-based eWOM to mobile-based eWOM. Finally, Sun, et al. 2006 studies eWOM from a communication perspective and explores its linkage with innovativeness, Internet usage, and Internet social connection. Overall, articles in this section provides a foundational understanding of eWOM and its relationship with advertising, communication, and marketing.

  • Chevalier, Judith A., and Dina Mayzlin. 2006. The effect of word of mouth on sales: Online book reviews. Journal of Marketing Research 43.3: 345–354.

    DOI: 10.1509/jmkr.43.3.345

    Focusing on and, this study examines the association of consumer reviews on book sales. The findings of this study confirm the effect of eWOM on sales. For example, it finds that review text is important compared to summary statistics.

  • Dellarocas, Chrysanthos. 2003. The digitization of word-of-mouth: Promise and challenge of online feedback mechanisms. Management Science 49.10: 1407–1424.

    DOI: 10.1287/mnsc.49.10.1407.17308

    Investigates the impact of Internet-based feedback mechanisms on organizations and explores how online feedback mechanisms differ from traditional word-of-mouth consumer processes.

  • Dwyer, Paul. 2007. Measuring the value of electronic word of mouth and its impact in consumer communities. Journal of Interactive Marketing 21.2: 63–79.

    DOI: 10.1002/dir.20078

    Examines the relationships of eWOM to consumer communities and explains how valued information constructs the social network. Findings suggest that consumer communities value informational content, and highly valued content leads to social network growth.

  • Fulgoni, Gian M., and Andrew Lipsman. 2015. Digital word of mouth and its offline amplification: A holistic approach to leveraging and amplifying all forms of WOM. Journal of Advertising Research 55.1: 18–21.

    DOI: 10.2501/JAR-55-1-018-021

    The authors propose that marketers should adopt a holistic approach by augmenting both digital and offline WOM. Specifically, these authors argue that digital WOM cannot replace traditional offline communications.

  • Hennig-Thurau, Thorsten, Kevin P. Gwinner, Gianfranco Walsh, and Dwayne D. Gremler. 2004. Electronic word-of-mouth via consumer-opinion platforms: What motivates consumers to articulate themselves on the Internet? Journal of Interactive Marketing 18.1: 38–52.

    DOI: 10.1002/dir.10073

    This highly cited article provides a definition of eWOM. The authors investigate motives of participation in eWOM in the context of consumer-opinion platforms. Consumers’ desire for social interaction, desire for economic incentives, concern for other consumers, and potential approval utility are identified as important antecedents that drive eWOM behavior.

  • Maslowska, Ewa, Edward C. Malthouse, and Stefan F. Bernritter. 2017. Too good to be true: The role of online reviews’ features in probability to buy. International Journal of Advertising 36.1: 142–163.

    DOI: 10.1080/02650487.2016.1195622

    Examines online consumer reviews as a form of eWOM and demonstrates that review features (i.e., valence and volume) have an effect on sales.

  • Okazaki, Shintaro. 2009. Social influence model and electronic word of mouth: PC versus mobile Internet. International Journal of Advertising 28.3: 439–472.

    DOI: 10.2501/S0265048709200692

    Employs a social influence model, proposes a model for consumer participation in eWOM, and compares the effects of PC-based and mobile-based eWOM. Results suggest that mobile-based eWOM participants scored higher on social intention, intrinsic enjoyment, and cognitive social identity than PC-based eWOM participants.

  • Phelps, Joseph E., Regina Lewis, Lynne Mobilio, David Perry, and Niranjan Raman. 2004. Viral marketing or electronic word-of-mouth advertising: Examining consumer responses and motivations to pass along email. Journal of Advertising Research 44.4: 333–348.

    DOI: 10.1017/S0021849904040371

    This is one of the first studies on viral marketing and eWOM in advertising journals. It focuses on consumer responses and motivations to pass along emails and provides practical implications for targeting strategies.

  • Roy, Gobinda, Biplab Datta, and Srabanti Mukherjee. 2019. Role of electronic word-of-mouth content and valence in influencing online purchase behavior. Journal of Marketing Communications 25.6: 661–684.

    DOI: 10.1080/13527266.2018.1497681

    The authors examine the influence of mixed neutral WOM valence and rich eWOM content on online purchase intention. Both qualitative analysis and content analysis were used to understand the role of various factors in affecting online purchase behavior.

  • Sun, Tao, Seounmi Youn, Guohua Wu, and Mana Kuntaraporn. 2006. Online word-of-mouth (or mouse): An exploration of its antecedents and consequences. Journal of Computer-Mediated Communication 11.4: 1104–1127.

    DOI: 10.1111/j.1083-6101.2006.00310.x

    Examines the antecedents and consequences of online word-of-mouth and establishes linkages between innovativeness, Internet usage, and Internet social connection. In addition, online forwarding and online chatting were found to be behavioral consequences of online word-of-mouth.

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