*6.2. Suggestions*

The empirical analysis of this study can o ffer some useful hints for advertisers to advance short-video ads. Below, we present some suggestions for advertisers and marketers to better develop health-related short-video ads:

(1) Consider various factors when promoting short-video ads.

The results of this study show that the five factors (social interaction, intrusiveness, informativeness, relevance, and perceived ease of use) defined in the model can all positively a ffect the perceived usefulness of short-video ads. Thus, we sugges<sup>t</sup> that advertisers should consider all five factors rather than focusing on one or some specific factors. For example, if advertisers neglect the 'relevance' factor, they might issue short-video ads in which the video content is irrelevant to the topic of the ads.

(2) Emphasize the social interactions of short-video ads.

Our study shows that social interaction is more influential to the perceived usefulness of short-video ads compared with other factors. Thus, we sugges<sup>t</sup> advertisers to pay more attention to the social interactions of short-video ads, which is a shortcoming of current short-video ads. As shown in Figure 1, current short-video ads provide few ways for social interaction. They are much like an introduction of a product, which neglect the use of social interaction. However, the results of this study show that social interaction is a key construct for enhance user acceptance of short-video ads. Therefore, we strongly sugges<sup>t</sup> advertisers to design social-interaction tools in short-video ads. For example, they can embed a voting button in a video by using new technologies like HTML5 to let video viewers submit their choices.

(3) Focus on users' perceived usefulness of short-video ads.

Through the mediating factor analysis, we found that users' perceived usefulness of short-video ads plays an important role in the impact path from the influential factors to users' purchase intention. Therefore, enhancing users' perceived usefulness of short-video ads is the key point of improving the e ffectiveness of short-video ads. On the one hand, advertisers should improve the quality of short-video ads, e.g., by increasing the informativeness and relevance of ads, or by providing new kinds of social interactions to attract users' attention. On the other hand, advertisers should avoid issuing any false advertisements, which are much harmful to consumers' confidence on products. Once users find that the short-video ads issued by an advertiser are over-claimed or false, the fast spreading of word-of-mouth on social network platforms will do considerable harm to the reputation of the advertiser.

(4) Advance ads on short-video social network platforms.

Short videos provide a free, real-time, and easy-to-access online way for enterprises to deliver ads to potential users. Recently, the number of the users on short-video social network platforms has shown a dramatical increasing trend, because live videos provide more attractive presentation than conventional textual web pages or tweets. Thus, it is important for enterprises to develop their short-video-based advertising systems and departments to advance ads on short-video social network platforms. Accordingly, the live short video as a new style of advertising could be utilized as a new tool to enhance the market competitiveness of enterprises.

#### **7. Conclusions and Future Work**

In this paper, we analyze the major factors that influence user responses to health-related short-video advertisements. Particularly, we made three contributions. First, we extended the Technology Acceptance Model (TAM) with new antecedents including social interaction (SI), intrusiveness (IR), informativeness (IN), and relevance (RE) to analyze the users' response to health-related short-video ads. We also introduced two mediate factors, i.e., perceived usefulness (PU) and ad attitude (AT), to reflect the influence of independent variables on the dependent variable named purchase intention (PI). To the best of our knowledge, this is the first study that extends the TAM model to analyze user acceptance of health-related short-video ads. Second, we conducted a survey on the Internet and short-video social network platforms and performed systematical data analysis over the surveyed data. The data analysis consisted of many aspects, including measurement model evaluation, structural model evaluation, and mediating e ffect analysis. The results showed that social interaction, intrusiveness, informativeness, relevance, and the TAM factors (perceived usefulness and perceived ease of use) had a significant influence on user acceptance of health-related short-video ads. Further, we found that users' perceived ease of use on health-related short-video ads could not significantly predict users' attitudes toward ads. This is a new finding that is contrary to previous studies in social media-oriented ads. Third, we presented reasonable suggestions for advertisers and marketers to better develop health-related short-video ads.

This study is beneficial for advertisers to realize the importance of understanding the e ffectiveness of health-related short-video ads. Base on the empirical results of this study, we gained some new findings, some of which are contrary to existing research. These findings are helpful to reveal the major factors that influence users' ad attitudes and intentions to purchase and to quantify the impacts of these factors on them. The suggestions made based on the empirical results of this study can provide some managemen<sup>t</sup> ideas for advertisers and academia to develop health-related short-video ads.

Some limitations of this study can be summarized as follows. First, although hundreds of valid questionnaires are theoretically enough to conduct data analysis, in this big data era, this number is relatively small to draw reliable and robust conclusions. Second, the results of this study have shown that the four antecedents, as well as the perceived ease of use, have significant influences on perceived usefulness, attitude, and purchase intention towards mobile live ads. However, the inherent theoretical basis has not been revealed yet. Third, the survey in this study has some limitations. Currently, we are only able to survey people on a Chinese short-video platform. The model, as well as the results, may not extend to people in other countries or on other platforms. In addition, as the respondents in the survey mainly cover young people (79.8% of them were under 30 years old), the results may not suit those advertisements that target old people.

Thus, in the future, there are some research issues that are worth further investigating. First, a further study on secondary data collected from some crowdsourcing platforms like Amazon Mechanical Turk [49] could be better to analyze user acceptance of advertising and marketing on short-video platforms. Second, because users' decision-making behavior could be impacted by other factors, future work can be focused on other possible factors, such as users' educational background and online experiences. Finally, in addition to the TAM model, it is also worth studying other research models within the big data and online community context [50].

**Author Contributions:** J.Z.: Conceptualization, project administration, supervision, and writing—original draft, J.W.: Data curation, formal analysis, investigation, and software. All authors have read and agreed to the published version of the manuscript.

**Funding:** This paper is partially supported by the National Science Foundation of China (No. 71273010).

**Acknowledgments:** We would like to thank the editors and anonymous reviewers for their suggestions and comments to improve the quality of the paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
