The codebook includes all independent variables for the analysis of influencing factors. To evaluate whether the items of the Weibo post characteristics in our codebook could influence the media effect of e-cigarette–related posts collected in our study, we used the Spearman bivariate correlation test to screen independent variables that were correlated with the numbers of reposts, comments, and likes. Then, we conducted 3 multiple linear regression analyses based on the number of reposts, comments, and likes. These analyses helped us identify the independent variables to be included in the final model. We used coefficient B (B) to indicate the amount of change in the dependent variables for one unit change in the number of reposts, comments, and likes. The SE measured the uncertainty of the regression coefficient estimates across the 3 models. We used standardized coefficient beta (β) to allow for a direct comparison of the relative influence of different variables in the regression analysis. T-value (T) tested the significance of the influence of independent variables on dependent variables. Variance inflation factor (VIF) detected multicollinearity between independent variables. A VIF of less than 10 is considered not to affect the model’s stability. We conducted tests of statistical significance using P<.05 as a threshold to report statistical significance.

This study observed the marketing strategies of e-cigarette companies and public behaviors on social media. This study did not involve human participants, as all data were acquired from public social media platforms. All the names of e-cigarette brands and users participating in the Weibo interaction are anonymous. Therefore, no additional ethical review was necessary.

Figure 1 shows this study’s screening process, which followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist. Multimedia Appendix 1 provides descriptive statistics for the characteristics of 863 posts from 32 selected Chinese e-cigarette Weibo accounts. Unlike traditional media, social media platforms facilitate individual interactions through comments and sharing. The number of reposts, comments, and likes reflected how e-cigarettes were perceived. Of the 863 Weibo posts, there were a total of 24,571 reposts, 8516 comments, and 22,272 likes. The average numbers of reposts, comments, and likes were 28.47 (SD 286.13), 9.87 (SD 41.27), and 25.81 (SD 237.63), respectively. Among these posts, the highest number of reposts, comments, and likes were 4903 (20%), 677 (7.9%), and 5029 (22.56%), respectively. The top 3 posts with the most reposts, comments, and likes all included interactive sweepstakes using e-cigarette and comparable products.

As Multimedia Appendix 1 shows, of the 863 Weibo posts, 449 (52%) posts described details of product features to attract others, including 351 (40.7%) posts relating to the shape of e-cigarettes and packaging attractiveness, 111 (12.9%) posts about flavors, and 48 (5.6%) posts highlighting the high quality and technique used in e-cigarettes. Out of 863 posts, 313 (36.3%) contained visible figures and 81 (9.4%) depicted fashion icons. Other visible characters with the highest percentage were everyday people (n=78, 9%), and the remaining were business people (n=26, 3%), sports people (n=16, 1.9%), celebrities (n=13, 1.5%), sales agents (n=12, 1.4%), and health professionals (n=2, 0.2%).

A total of 101 (11.7%) posts had information on product promotions. Among them, 10 (1.2%) posts involved monetary promotional offers, including coupons, two-for-one offers, and discount sales. Moreover, 83 (9.6%) posts were related to nonmonetary promotions including giveaways and free samples, while 8 (0.9%) posts contained both incentives.

A total of 790 (91.5%) Weibo posts did not mention any information on purchase channels. The rest (n=73, 8.5%) still contained information on purchase links, phone numbers of offline purchases, and other purchase channels.

Of the 863 posts, 548 (63.5%) interacted with fans, indicating that most posts tried to entice Weibo users to engage through various methods, including reposting, commenting, and clicking likes. A total of 538 (62.3%) posts featured hashtags; 41 (4.8%) encouraged fans to repost, comment, and like; and 29 (3.4%) interacted with fans by collecting stories and ideas.

E-cigarette–related posts generated interactions with Weibo users through a variety of topics. In 45.4% (n=392) of the posts, interaction topics were related to products. Current event topics accounted for 21.1% (n=182) of the posts. Topics related to interactive sweepstakes accounted for 8.7% (n=75). The post number of brand-related topics, “soul-soother” or emotional issues, and Weibo account promotion were 73 (8.5%), 15 (1.7%), and 1 (0.1%), respectively. Furthermore, joint promotion with other brands and promoting the Weibo accounts of brands by sending gifts were also the main themes of hashtag topics.

Of the posts, 687 (79.6%) posts had no age restriction claims for minors to purchase or use e-cigarettes, 130 (15.1%) restricted minors’ use but did not limit their purchase, and 6 (0.7%) restricted minors’ purchases but did not limit their use. Only 40 (4.6%) posts restricted both purchases and use by minors. Meanwhile, only 24 (2.8%) posts provided health warnings.

We put all the variables in the codebook into the Spearman bivariate correlation test to screen out the independent variables that had a significant correlation with the dependent variable. These variables were included as independent variables in multiple linear regression. A multiple linear regression analysis was conducted to examine the effect of e-cigarette postmarketing strategy features on communication outcomes. The overall statistics of the 3 regression models are presented in Table 1. The results are presented in Table 2.

Contents including engagement via posts encouraging reposts, comments, and likes (P<.001), and engagement topics related to e-cigarette brands were positively correlated with the number of reposts (P=.009). Posts highlighting nonmonetary incentives (P=.004), posts with age-restriction statements (P<.001), engaging via stories and idea collection (P<.001), and engagement topics related to products (P<.001) and current affairs (P=.002) had a positive effect on the number of comments. Engagement topics related to brands (P<.001) or interactive sweepstakes (P<.001) had a more significant positive effect on the number of likes than those without. Posts that mentioned purchase channels significantly negatively affected the number of reposts (P=.004) of e-cigarette posts. Posts that did not mention any incentives had a negative impact on receiving likes of posts (P<.001). Posts that had no product information had a negative correlation with the number of likes (P=.02).

We analyzed Weibo posts by e-cigarette brands and gained valuable insight into how e-cigarette promotion information spreads and proliferates via social media. Weibo posts by 32 official e-cigarette accounts collectively received many likes, comments, and reposts, gaining widespread attention. Our results show that e-cigarette content exposure on social media may attract Weibo users’ attention and can successfully shape more positive attitudes toward e-cigarettes. Existing research has also shown that social media marketing of e-cigarettes has a particularly positive impact on teenagers’ attitudes and risk behavior [49,50], which may pose a threat and challenge to youth e-cigarette use and global public health.

We observed several marketing tactics employed by e-cigarette companies on Chinese social media, documented as emphasizing attractive product features, using trendy characters, implicit promotions, downplaying health concerns, and engaging with Weibo users in various ways. These posts were visualized through pictures or videos, catering to teenagers’ reading habits and the demand for more impactful content [51,52]. The persuasive power of images was crucial in making e-cigarette-related information more attractive [42]. Few posts mentioned health warnings and age restrictions.

Highlighting attractive product characteristics was one of the most significant e-cigarette marketing tactics on Weibo. Approximately half of the Weibo posts emphasized product characteristics, particularly showcasing unique shapes and attractive packaging, which may appeal to teenagers and lower their perceptions of e-cigarette risks [38,39]. Even though only a small number of posts mentioned flavors, the promotion of flavors through beautifully designed posters and appealing flavor descriptions should be further monitored. This finding revealed that flavor features attract teenagers [22,40-42], as it is the most common reason for youth e-cigarette use [43]. In particular, some e-cigarette brands marketed flavors that represent Chinese culture, such as green tea. To the best of our knowledge, this is the first study to identify a marketing strategy that builds a responsible corporate image by promoting efforts to protect traditional Chinese culture. Among all the posts with images of people, fashion icons and ordinary people accounted for the largest proportion. The latest research suggests that attention should be paid to graphic characters in e-cigarette advertisements, as fashion models or ordinary people may glorify or normalize e-cigarette use among teenagers [53].

Even after online sales supervision was tightened in 2020 [19], a small number of e-cigarette companies continue to provide relevant promotional information on Weibo and continue to look for implicit promotion methods. The impact of nonmonetary incentives was uncertain in our findings. However, the existing published scoping reviews reveal that e-cigarette companies worldwide use monetary and nonmonetary incentives, such as promotional codes, discounts for new customers, coupons, and giveaways, in addition to e-cigarette advertising [44,54]. Double incentive strategies likely create excitement and reciprocity, making teenagers feel grateful toward the brand, thus promoting a positive perception of that e-cigarette brand [55].

The scarcity of age restrictions and health warnings in e-cigarette posts was common, potentially reducing Weibo users’ sense of caution. Previous studies have also highlighted the lack of emphasis on health issues and warnings by e-cigarette companies on social media [1,5,21,56,57]. Previous studies have found nicotine warnings of different designs could influence young people’s perception of harm and use intention to varying degrees [58]. In our study, we found relevant statements were in small print and vague, which might not draw enough attention or mislead teens. Therefore, warnings and statements should be carefully designed to alert or minimize appeal to teenagers. Additionally, such restrictions should be strictly regulated and monitored on social media.

One remarkable new finding regarding online engagement is that interactive sweepstakes on Weibo significantly expanded the influence of e-cigarette brands. In our study, the 3 posts with the highest reposts, comments, and likes all had interactive sweepstakes. Web-based contests and sweepstakes are also frequently utilized on social media platforms favored by young people in other countries [44,46]. A previous study emphasized the success of sweepstake-based marketing in enhancing user attention and engagement [59]. Reposts, comments, and likes are measures of user engagement [45,60] and indicators to increase the exposure of posts [61,62]. Web-based interactivity is a unique feature of social media that can create greater brand exposure and attention. Digital e-cigarette marketing involves various interactive methods to foster greater engagement. Our results show that various types of interaction positively impact the media effects of e-cigarette Weibo posts to varying degrees.

Based on the content analysis, our study found that e-cigarette companies constructed a unique culture to appeal to both e-cigarette users and potential users on Weibo. Interactive strategies on social media help e-cigarette brands establish an online presence that posits e-cigarettes as fashionable trend and lifestyle choice, potentially creating a community and identity for vapers and fostering a sense of belonging and loyalty. This conclusion is consistent with the existing research [63].

Our results uncovered many posts with hashtags, similar to the results of other studies [4,21]. Many e-cigarette Weibo accounts post hashtags with their brand name to build a vaping community associated with a specific e-cigarette brand. Using brand-specific hashtags can further construct social bonds and common beliefs around e-cigarettes [1,64]. Posts including hashtags unrelated to tobacco directly are common [4], and existing studies revealed vaping posts contained health lifestyle hashtags [65]; thus, teenagers may view specific hashtags posted by e-cigarette companies without searching for e-cigarette-related content, which can greatly expand a post’s reach. For example, one of the posts included hashtags such as #daretoimagine (“Gan Yu Xiang Xiang” in Chinese). Moreover, Chinese e-cigarette marketing on Weibo combines mainstream culture and subculture through hashtags related to current events. For example, some hashtags linked the new technology of e-cigarette products to China’s overall technological power. Through this marketing strategy, e-cigarette Weibo posts achieve broader coverage.

China gradually strengthened regulations regarding e-cigarette marketing after this study was completed. The latest policy tightens restrictions on the manufacture and sale of e-cigarettes, specifically prohibiting the sale of flavored e-cigarettes, tobacco flavors, and private company atomized e-cigarettes [20]. After the ban, there has been a massive decline in the e-cigarette marketing strategies we observed in this study. However, more implicit posting, instead of direct promotion content on social media, may be a way to circumvent these restrictions. Until May 10, 2024, among all the 32 Weibo accounts of e-cigarette companies we investigated, 6 (18.9%) Weibo accounts continued updating posts on Weibo after the published ban in 2022 [20], and 1 (3.1%) e-cigarette company is still updating posts on Weibo as of April 2024. The content posted by these e-cigarette companies on Weibo did not directly promote e-cigarettes. Rather, most posts described e-cigarette flavors covertly via references to coffee, desserts, and other food-related items.

Our findings suggest that hidden online promotional content poses a significant threat and challenge to youth e-cigarette use and global public health. Thus, regulatory policies should be implemented to protect teenagers from marketing information regarding e-cigarettes and other tobacco products. Constant surveillance and nationwide legislation of internet marketing activities are essential to protect teenagers from ambiguous, inaccurate, or even deceptive information about e-cigarettes, as teenagers and other vulnerable populations are more susceptible to marketing claims [31,32,66]. There should be clear legal provisions that e-cigarette–related information must include explicit health claims and age restriction statements in large print [67,68]. Furthermore, more relevant health education activities and campaigns for teenagers should be conducted, and health communication media should give more prominence to issues related to e-cigarette prevention and control.

In response to the rapid growth of e-cigarette marketing, China has been intensifying its efforts to regulate e-cigarette internet marketing, which could serve as a reference for enhancing electronic cigarette oversight globally.

This study had several limitations that need to be addressed in future research. First, our study focused on the official Weibo accounts of e-cigarette brands, neglecting other stakeholders and social media platforms involved in e-cigarette social media marketing. Second, our data collection did not consider the possibility of data manipulation by e-cigarette companies. Third, although the existing research shows that e-cigarette marketing is mainly targeted toward teenagers, we could not confirm whether the e-cigarette Weibo marketing strategies are directly reflected in this age group due to the anonymity on social media. Direct evidence of the relationship between Weibo e-cigarette marketing and its impact on teenagers still needs to be teased out. Future research could gather data from more countries and platforms to conduct a more internationally comparative study.

The findings reveal marketing tactics used by e-cigarette companies on Chinese social media, and their influence on the numbers of reposts, comments, and likes on posts. Despite nationwide regulations, e-cigarette companies are finding ways to strengthen their marketing presence on Weibo and indirectly target adolescents, often without health warnings or age restriction disclaimers. E-cigarette marketing on social media requires global attention and coordinated efforts. Our study provides insights into how to strengthen the supervision of invisible marketing on social media of e-cigarette companies.