Customer eWOM Engagement in Online Brand Communities: A Systematic Literature Review

Online brand community is an important channel for the occurrence and dissemination of electronic word-of-mouth (eWOM) communication. Building an online brand community is also a strategy for many companies in customer relationship management and marketing. In the management practice of online brand communities, it is found that consumers’ eWOM engagement intentions are not high, which affects the prosperity and development of online brand communities. Therefore, it is urgent to enable practitioners and researchers to have a more comprehensive and in-depth understanding of the characteristics and research ideas of consumers’ eWOM engagement intentions in online brand communities. This study aims to summarize the unique characteristics of eWOM engagement in online brand communities, which theories have been applied frequently, and provide directions and suggestions for future in-depth research on eWOM engagement intentions. This study searched the Scopus and Web of Science databases for a systematic review of studies that are highly correlated with consumers' eWOM engagement intentions. This study summarizes three unique characteristics of consumers’ eWOM engagement intentions in online communities: eWOM engagement is customer engagement on a behavioral level; segmentation of user groups is necessary; and the relationship between consumers and brands plays a key role. This study finds that the most commonly used research method is quantitative research, and the most applicable theories include social identity, social exchange, social capital, psychological ownership, and organizational support theories. Researchers who want to research consumers’ eWOM engagement intentions in online brand communities in the future can refer to the three directions summarized in this study: further refine and supplement the antecedents and consequences of consumers’ eWOM engagement intention; consider the subdivision of consumer groups to research consumer attitudes and behavioral motivations; include consumer demographic characteristics, cultural characteristics, and external environmental influences in the research.


Introduction
The Internet has changed the way consumers obtain information.Users can express their opinions about brand products and services on various platforms, obtain information, and seek advice on them.In this process, the participation of electronic word-of-mouth (eWOM) occurred (Tabassum et al., 2020).By liking, posting, posting, and commenting, consumers can express their opinions on products and services through social media, brand portals, and forums (Donthu et al., 2021).At the same time, brand organizations and companies can receive instant feedback from consumers.Electronic word-of-mouth communication breaks geographical restrictions, and users' thoughts and opinions can be quickly disseminated through the network platform (Donthu et al., 2021).Frequently word-of-mouth communication will help subsequent consumers quickly understand products and services as the basis for purchasing decisions and help brand companies understand consumers' viewpoints for product improvement and innovation.
The communication channels of eWOM include social networking sites, forums, and review sites (Bhaiswar et al., 2021).Online brand communities, as geographically unconstrained online communities based on social interaction and the relationship between consumers and brands, are also one of the communication channels of eWOM engagement (Amoah et al., 2022;Bilro & Loureiro, 2023;Muniz Jr & O'guinn, 2001).The establishment of an online brand community is beneficial for consumers to cooperate more closely with the brand side and for brand managers to understand the behavior of consumers (Karjaluoto et al., 2014).A review of the overall research progress is needed to summarize the current research status and guide future research.Based on the development of literature on users' intention to engage in eWOM in online brand communities, these literature needs to be comprehensively reviewed and analyzed.This study attempts to systematically review empirical research about users' eWOM engagement intentions in the context of online brand communities.This study aims to identify applicable theories to study this area, summarize the characteristics of eWOM engagement intentions, and research trends in this area through a systematic review of the existing literature on eWOM intentions in online brand communities.In order to achieve this goal, we have refined five small research objectives.RQ1: Which theories and methods are used in the articles selected for this literature review?RQ2: What are the unique characteristics of consumer eWOM engagement in the context of online communities?RQ3: What research gaps are mentioned in the empirical studies reviewed in this study, and what are the recommendations for future research?
In order to answer the above questions, this article searches for keywords in Scopus and Web of Science and screens the search results.In the selected articles, we summarize the characteristics of eWOM engagement intention of online brand community consumers, the theories frequently applied in the field, the characteristics of eWOM engagement intention, and recommendations for future research.

Methods
The research method of systematic literature review locates, evaluates, and synthesizes existing research evidence by collecting a large amount of literature to produce actionable knowledge (Denyer & Tranfield, 2006).This study systematically reviews the empirical research on users' eWOM engagement intention in online brand communities.According to relevant research, the research steps of systematic literature review include: specifying the article search strategy, determining the scope of the article search, determining the article inclusion criteria, filtering articles based on article quality, and conducting a systematic review of the remaining articles.(Kamboj & Rahman, 2015;Tranfield et al., 2004).

Search Strategy
Scopus is the world's most considerable literature abstract and scientific research information citation database, and the Web of Science includes authoritative and influential journals in various disciplines (Comerio & Strozzi, 2019).Hence, the data sources of this study are Scopus and WOS databases.The search formula is ((TITLE-ABS-KEY ("online brand community") OR TITLE-ABS-KEY ("online brand communities") OR TITLE-ABS-KEY ("virtual brand community") OR TITLE-ABS-KEY ("virtual brand communities") OR TITLE-ABS-KEY ("online community") OR TITLE-ABS-KEY ( "brand community" ) ) AND ( TITLE-ABS-KEY (women) OR TITLE-ABS-KEY ("eWOM participation") OR TITLE-ABS-KEY ("eWOM engagement") OR TITLE-ABS-KEY ("eWOM engagement intention") OR TITLE-ABS-KEY ("eWOM intention" ) ) ).After searching, 63 articles were obtained.

Inclusion/Exclusion Criteria
The inclusion criteria • Topic of studies Only articles involving eWOM engagement in online brand communities were considered.The title and abstract/or keywords of the article should contain "online brand community" or "virtual brand community" or "online community" or "virtual community" or "brand community" and also include "eWOM" or "eWOM participation" or "eWOM engagement" or "eWOM intention".
• Type of studies Although articles on user eWOM engagement in online brand communities exist in conference papers, master and doctoral theses, books, editorials, erratum, conference reviews, short surveys, and research reports, only journal papers are considered in this study (Donthu et al., 2021;Gumparthi & Patra, 2020).

• Study design
The attention of this study is mainly focused on research on the antecedents and consequences of user eWOM engagement in online brand communities.
• Language Only articles written in English were considered in this study because English articles are easier to reproduce and review (Kamboj & Rahman, 2015).
• Publication status and publication year Since the number and citations of literature on eWOM engagement in online brand communities published in Scopus and WOS databases before 2013 were scarce, they were not included in the scope of this study.We only consider articles published in journals indexed by Scopus or Web of Science in the past ten years.

The Exclusion Criteria
Articles will be excluded if: no full text is found; only an abstract; no abstract exists; no references; non-peer-reviewed journals; irrelevant to the topic despite the title or abstract or keywords containing keywords.

Article Screening
Figure 1 shows the process of screening articles.Initially, according to keywords and search formulas, the two databases Scopus and WOS were searched, and a total of 111 articles were obtained.After removing duplicate articles, removing irrelevant articles, removing only nonfull-text articles, removing conference papers, removing articles with low quality or deviated from the topic after full-text browsing, and adding seven articles supplemented by manual search on the citation network, the remaining 38 valuable articles are yet to be analyzed.
Figure 1 The process of screening articles

Summary of Included Studies
Figure 2 presents the research design the authors prefer when studying consumer eWOM intentions within online brand communities.The statistical results show that quantitative research dominates this field, accounting for 79%.The number of articles conducting qualitative research is currently the smallest, with only two among the selected articles, and the rest of the studies used a mixed research design.
Figure 2 The research design the authors prefer Figure 3 shows what techniques researchers use when analyzing data in the field of consumer eWOM willingness to participate in online brand communities.Among them, using regression analysis techniques to confirm the impact relationship between variables occupies the most significant proportion, accounting for 76% of the total.Some researchers have combined text analysis methods based on regression analysis, and the data source is the text content published by consumers in online brand communities.Some researchers used systematic literature review and bibliometric analysis techniques.Some researchers have also used data analysis techniques such as thematic analysis, Netnography, and multigroup comparison.• EWOM engagement is customer engagement on a behavioral level Consumer engagement refers to "the extent to which consumers are willing to invest their own personal resources -time, energy, money -in the brand, beyond those resources expended during purchase or consumption" (Ananda et al., 2019).Customer engagement includes three levels, emotion, cognition, and behavior (Brodie et al., 2013;Perez-Aranda et al., 2021).The emotional level refers to customers' positive or negative feelings about company activities.The cognitive level refers to whether customers are interested in company activities.The behavioral level includes participation, events, co-creation, and word of mouth.EWOM engagement is the result of consumer engagement in the online brand community at the behavioral level (Ananda et al., 2019;Jani et al., 2018).
• Segmentation of user groups Many researchers have segmented consumer groups when exploring eWOM engagement intentions in online brand communities.Lejealle et al (2022) proposed that Members of online brand communities can be categorized according to their level of engagement as novices, tourists, moderate supporters, and experts when studying the factors that affect consumers' word-of-mouth intention and co-creation.Some researchers divide online brand community members into active consumers and non-active consumers (Mousavi & Roper, 2023).Active consumers (posters) and non-active consumers (lurkers) are two distinct personality traits.Active consumers believe they have enough power to publish information, while non-active consumers think they have nothing to share (Haikel-Elsabeh et al., 2019).Posters had a stronger need for social identification, and lurkers had a more substantial need for high-quality information (Mousavi & Roper, 2023).The researchers also divided consumers into heavy users and light users according to how much time and energy they are willing to spend in online brand communities.Users with more knowledge will see themselves as more integrated into the online brand community (Ruiz-Mafe et al., 2018).Heavy users are more likely than light users to join the brand's incentive programs (Ruiz-Mafe et al., 2018).
Consumers are also divided into information seekers, opinion passers, and opinion leaders (or opinion givers) based on their eWOM engagement type (Ananda et al., 2019;Qiao et al., 2021;Yuan et al., 2021).Opinion leaders are an essential source of information in online brand communities (Ananda et al., 2019;Hussain et al., 2020).Information seekers seek the opinions of others by reading their reviews, conversations, and emails to make purchasing decisions (Ananda et al., 2019;Hussain et al., 2020).Ananda et al (2019) mentioned that different eWOM behaviors, such as pass-on and endorsement, have different drivers.Another researcher expressed this division as knowledge seekers and contributors (Chia-An Tsai & Kang, 2019).Knowledge seekers sacrifice their knowledge and energy in exchange for valuable knowledge, and knowledge contributors contribute their knowledge in exchange for the realization of reputation and self-worth (Chia-An Tsai & Kang, 2019).It can be concluded that Individuals will participate in different types of eWOM behaviors, and different eWOM behaviors have different motivations (Qiao et al., 2021).

• The key role of the relationship between consumers and brands
Although the research on customer engagement in online brand communities has attracted more and more attention from researchers, most of the research subjects are consumers or communities and rarely take brands as the subject (Kumar, 2021).The online brand community is built around the brand, and consumers join and participate in the online brand community to a certain extent because of their interest in the brand and their recognition of the brand concept and brand image.When the brand content and the self-concept of consumers coincide, the transfer of brand information becomes a means of self-expression (Kim et al., 2014).In order to study the relationship between consumers and brands, the characteristics of online brands must be addressed (Bilal et al., 2022).Providing consumers with brand information that enhances their personal image will attract them to the brand and then participate in eWOM activities (Maree & Van Heerden, 2021).The higher the degree of brand identity and the closer the relationship with the brand, the more likely consumers are to develop positive behavior (Kim et al., 2014).When the online brand community makes use of real-time conversations to facilitate customer interaction from a technology perspective while providing content-based topics that generate consumer interest and are relevant to the brand, consumers are more likely to provide and share brand information (Taylor et al., 2023).

Theories
The following table summarizes the theories used in the selected articles and the frequency of use of the theories.It can be concluded that social identity theory, social exchange theory, social capital theory, psychological ownership theory, and organizational support theory are the mainstream theories in the field of consumers' eWOM engagement intention in online brand community.Social exchange is the foundation of the relationship between consumers and the brand community.The original content shared by consumers is a resource in the hands of consumers, and the community should reward consumers in exchange (Taylor et al., 2023).Jani et al (2018) also explained that under an interactive brand page, the positive behavior of consumers is the return of incentives received by consumers, which is in line with the principles of social exchange theory.Some researchers have studied the predictors of eWOM from the perspective of the benefits that online brand communities can provide consumers.Bilal et al (2022) emphasized the importance of high-quality services, reliable information that the community can provide.Ananda et al (2019) reported that information search needs are the driving factor for a large number of consumers to join online brand communities, and consumers whose information needs are satisfied are likely to participate in pass-on behaviors.Tsai and Kang (2019) pointed out that eWOM communication in online brand communities will bring the realization of reputation and self-worth to knowledge contributors.Researchers have also noted the role of organizational support provided by online brand communities in promoting positive consumer behavior (Chia-An Tsai & Kang, 2019;Molinillo et al., 2020;Mousavi & Roper, 2023;Phan et al., 2020).
Some researchers analyzed the factors that affect consumers' attitudes and behaviors in online brand communities from the social identity perspective.Kim et al. (2014) concluded that the higher the degree of brand recognition and the closer the relationship with the brand, the more likely consumers will form brand information forwarding behavior.Valmohammadi et al. (2023) also proposed that the more consumers feel identified with a brand community, the more likely they are to engage with eWOM.The findings of Romero and Ruiz-Equihua (2020) show a positive relationship between firm identity and community identity, and both positively affect the creation of positive content mediated by selfenhancement.The manifestations of community identity include commitment to community goals, reciprocity with community members, compliance with common norms of the community, and satisfaction with the common needs of community members (Molinillo et al., 2020).

Suggestions for Future Research
According to the summary of the selected articles' recommendations for future research, future research can be carried out from the following three directions.Firstly, research on the antecedents and consequences of customer engagement in online brands is still in its infancy and awaits to be supplemented and expanded by future research (Kumar, 2021;Maree & Van Heerden, 2021).Whether variables such as service innovation and brand image are dependent variables that affect brand love and consumer eWOM, intention remains to be tested (Bilal et al., 2022).Future research could identify psychological ownership (Kumar, 2021), brand personality Hsu et al (2022), brand equity Hsu et al (2022), social interaction Ruiz-Mafe et al (2018), service innovation Bilal et al (2022), and brand image Bilal et al (2022) as antecedents of customer engagement.A suggestion for future research from Rossmann et al ( 2016) is that more factors based on motivation, content, and social role that affect eWOM engagement still need to be studied.In addition, other behavioral participation of consumers in online brand communities can also be used as research objects.Future research can incorporate more theories that help understand the behavior and attitude of community members and take eWOM valence Kim et al (2014), the duration of community use Kumar & Nayak (2019), visit frequency (Kumar & Nayak, 2019), brand attachment Anaya-Sánchez et al (2020) into consideration as dependent variables.
Secondly, some researchers suggest that research should be conducted with a more detailed segmentation of consumer groups.Mousavi and Roper (2023) suggested that future research should further understand the different roles of inline brand community members, as well as the motivations for different levels of participation.Kumar (2021) argues that members can be segmented within a community based on heterogeneity to discuss predictors of customer engagement.Karjaluoto et al (2014) propose that researchers can compare the behavior of members and non-members of online brand community.In addition, when choosing data collection methods, future research can consider asking about consumers' motivations to engage in the community in detail through interviews.
Thirdly, some researchers have pointed out that demographic characteristics, external environmental factors, and factors should be taken into account in research on consumers' eWOM engagement willingness in online brand communities.Jeong and Koo (2015) proposed that future research should take multicultural social groups as research samples.Qiao et al (2021) suggest that future research needs to consider mapping consumer age, gender, and economic status and influence consumer behavior and attitudes.Perez-Aranda et al ( 2021) suggested future research could take into account organizational characteristics such as size, category, or management type, as well as individual characteristics such as age and gender, the valence of eWOM, and consider the indirect effects of organizational commitment and organizational capability on eWOM strength.

Conclusion
This study provides a comprehensive review of current research in the field of consumer eWOM engagement intentions in online brand communities, providing a clear panorama for researchers and practitioners who want to understand the research findings in this field.In a practical sense, this research can help managers of online brand communities to quickly understand the current research results and improve strategies for managing communities based on the research results to promote consumers' eWOM participation intentions.
Regarding the research contribution, this study provides ideas and suggestions for researchers who want to engage in the in-depth analysis of eWOM engagement intention in online brand communities.However, this study also has certain limitations.The data in this study only come from two databases, Scopus and Web of Science, so more data sources must be available.Future systematic literature review studies could consider synonyms of eWOM and add other databases as literature data sources when conducting subject heading searches.In addition, future systematic literature review studies can use more diverse methods to ensure the comprehensiveness of data sources when conducting literature searches.

Figure 3
Figure 3 Data analysis techniques

Table 2
The frequency of theories