1. Introduction

Gen Z consists of people born between 1997 and 2012 who are young, brave and creative to face a more uncertain future due to the COVID-19 pandemic [1]. Social distances and lockdowns not only precipitate an unprecedented global economic crisis - unemployment and collapse of numerous small and medium-sized businesses - but also bring overwhelming and stressful challenges to human mental and physical health. During the quarantine, “social media platforms have become major globalized influential communication spaces” [2] and social media alone accounts for 35% of a vast increase in digital communication [3]. Gen Z, raised by digital technology, are accustomed to technologies like social media [4], and their social media engagement has increased by 61 per cent during the pandemic [5].

The information on social media during the pandemic impacts Gen Z’s world outlook [6] and behaviors, which leads global merchants to consider e-commerce an arresting prospect [7]. Boston Consulting Group surveyed consumers aged 16 and above in North America and East Europe and concluded that, during the pandemic, Gen Z’s behaviors and spending had been affected and altered “more dramatically than older generations have” [8]. Their spending behavior decreased, and according to the research data of 336 people from Gen Z, nearly 20% decrease of offline shopping shifts to online channels. The trend of growth of e-commerce calls for important planning for the future [9] so that companies and marketers are eager to take advantage of Gen Z and achieve their social media marketing strategies.

The hypothesis is that the utilization of trending topics during the pandemic, such as social issues, influencer marketing and live streaming on social media, in marketers' social media marketing strategies impacts Gen Z's thoughts, such as recognition of gender inequality, values, such as view of money, and behaviors, such as the pursuit of a new vocation. These results may further attract Gen Z, cause companies to earn or lose large profits, and gain positive or negative word of mouth. Finally, these demonstrations warn marketers and society to utilize the trends among Gen Z properly, instead ignoring the possible negative impacts of the utilization on Gen Z for the pursuit of profits.

2. Macroscopic Level: Utilizations of Trending Topics Discussed among Gen Z

As out-of-home advertising, cinema advertising, and print advertising fell, and in-home media usage increased since the pandemic [10], marketers connect trending topics discussed during the pandemic via social media with their products to draw Gen Z consumers' attention. The macroscopic level generally introduces two categories of utilized trending topics and why they attract Gen Z on social media, especially since the pandemic. The macroscopic level lays the foundations for the microscopic level to introduce what marketers have done with these trending topics to pursue positive word of mouth since the pandemic.

"Trending topics" among Gen Z discussed in this paper, firstly, refer to debated social issues, including messaged values and thoughts mainly based on gender inequality and gender stereotypes. These social issues became more severe and public during the pandemic. Due to COVID-19, female job loss rates are about 1.8 times higher than male job loss rates globally [11]. Women "are more likely to be employed in the informal sector" with "few protections against dismissal or for paid sick leave and limited access to social protection" [12] or sectors like restaurants, hotels and tourism, which are hardest hit by the crisis [13]. Furthermore, women are more likely to be exposed to the virus because they "make up 70 percent of the health workforce" and most health facility service staff like cleaners. The pandemic exposes gender inequality and gender stereotypes regarding occupations and domestic behaviors as women have unequal job opportunities, and people usually assume women are good at cleaning and have to work in the service industry. In addition, according to the UN report, violence against women has been increasing globally during the pandemic, and many reported cases increased by more than 25%, and some have doubled. Also, during the pandemic, people, especially Gen Z, are experiencing more cyber violence, such as body shaming [14], because with increased screen time and decreased physical activity, people are more likely to be exposed to thin or athletic ideals [15]. People, especially women, suffer more from appearance anxiety and body dysmorphic disorder. Women are often expected to be accommodating and thin. Although men are also expected to be muscular, women have received much more pressure on body image from society, and "body dissatisfaction for females is significantly higher than for men" [16]. These further expose social issues of gender inequality and gender stereotypes on personality traits and physical appearance.

These social issues and their messaged values collide with Gen Z's existing ideas. Then Gen Z generates their cognition of social issues like gender inequality and stereotypes, and discusses and spreads the contents extensively and intensely on social media. According to a Student Bean survey in November 2021, 86% of Gen Z use social media to get their news [17] and table one of Statista's survey in 2022 shows social media is Gen Z's primary news source as 68% of them at least use Social media to read the news a few time per week [18]. Moreover, according to Figure 1, of the 336 people surveyed, 53.27 percent said their use of social media to read news and entertain had increased during the pandemic, while 30.95 per cent's use remained the same. Even national and international organizations post news actively on social media to invite young users to interact [19]. Hence, marketers also planned to connect frequently discussed news of social issues among Gen Z with their products on social media to promote the products and encourage word of mouth.

Table 1: Gen Z news consumption sources in the U.S. 2022.

Figure 1: Changes of frequency of using social media since the pandemic.

Secondly, "trending topics" refer to figures like influencers and celebrities who thrived during the pandemic and collaborated with technologies invented or further developed during this time, such as live streaming. "Influencer" defines individuals with a large group of social media followers who usually promote a specific product, theme or lifestyle. In the context of the COVID-19 pandemic, some countries like Indonesia and Finland [20] use influencers in their crisis communication strategies, like voicing support or concerns about restrictions or vaccination. This demonstrates influencers' extensive popularity and dynamism of the communities they have built so that influencers are today major operators in marketing and commercial communication - influencer marketing's worth is expected to "grow from 13.8 billion dollars in 2021 to 15 billion dollars in 2022". For example, Dunkin' Donuts, an American multinational coffee and doughnut company, came to a long-term sponsorship with Charli D'Amelio, the most followed TikTok creator. It released a beverage called "The Charlie", and Charli's promotion "led to a 57% increase in app downloads on launch day and 45% increase in cold brew sales the next day" [21]. There is another example to show the power of influencers and celebrities. Since early 2022, the hashtag Follow Will Liu has always occupied the homepages of various Chinese social platforms. Will Liu is a Chinese actor who has used social media, Tiktok, to live broadcast his workout tutorial, and the users, 60% of whom are Gen Z, follow him to work out. Liu and his wife, Wang, "gained more than 64 million followers within a single month and their livestreams have been viewed roughly 100 million times" [22]. The sports label Fila spotted their popularity and spent $2.53 million to be worn and recommended by the pair in their live streams for two days to drive sales.

97% of Gen Z consumers use social media as their top source of shopping inspiration [23], and almost half (44%) of Gen Z has decided to purchase based on social influencers' suggestions [24]. Moreover, Hodge says there was a 76% increase in live-stream shopping purchases during the pandemic and "80% of marketers think live-stream commerce will be an important part of sharing products in the coming years" [25]. More specifically, Frost & Sullivan estimates that "over $400 billion of products will be sold through this type of channel in China by 2022" [26]. While live-stream shopping exploded the most in Aisa, there is a growing interest in live-stream shopping among American consumers. James Bay from Wunderman Thompson, a global marketing communications agency, calls for the world to learn from the explosion of live streaming commerce in China [27]. Through live-stream on social media, the celebrities or influencers act like a friend to have a conversation with the consumers, which is part of Gen Z and millennial's lifestyle curation [28] so that consumers are 21 times more likely to shop from the retailer on these social engagement channels than other traditional e-commerce channels. Finally, marketers collaborate with influencers and celebrities to use their extensive popularity to promote products. Some ask influencers to do live streaming, not simply post photos, to talk with consumers and sell products on social media. This gives users a chance to interact with influencers and retailers, further market their products, and progress in generating positive word of mouth.

3. Microscopic Level: Utilizations of Live Commerce and Influencer Marketing among Gen Z

Studies in respect of particularities of Gen Z have proven that this generation tends to attain information actively and efficiently, which mean they prefer to acquire more content at a time and interact more with sellers while purchasing, so that live commerce becomes their propencity [29]. In addition, during the pandemic when out-of-home marketing was jeopardized, influencer marketing is emerging and Gen Z, raised by digital technology, are accustomed to social media and its main components, influencers. Accordingly, nowadays, live commerce and influencer marketing, one category of trending topic in this paper, are dominant sources regarding products' information for Gen Z. Marketers' specific actions, based on utilizing trending topics including social issues, influencer and live commerce, are divided into two major categories - building a general climate and fan economy.

3.1. Building a Climate

Influncers' outputs on social media are often classified into elaborate vertical categories which the platforms can recommend goods and services to users with specialized interests and needs. Under this circumstance, users are separated into diverse interest circles, and users with the same interests are united in the same interest circle. To illustrate, fashionable individuals watch the same videos about outfits or makeup, and video game addicts watch the same video game commentaries. There are sub-circles in interest circles, for example, western goth makeup, Korean natural makeup in beauty circle, and the "color blocking" trend or oversize style in the fashion field. Platforms utilize the knowledge of users' specific interests to earn profits from potential consumers, such as recommending cosmetic applicators to beauty lovers, game currency and equipment to video game fans. The thought patterns of all these circles or communities form microclimates vary because these microclimates are usually impacted by different macroenvironments, whose components are social and cultural forces, economic climate and so forth. The influential strategies could create or connect a trend with own products and then strengthen or change the impacts of components of macroenvironment on consumers from microclimates to raise popularity. For example, in different regions, makeup tutorials and OOTD (outfit of the day) sharing demonstrate different beauty standards and body image, all built on particular aesthetic views produced by social and cultural forces. These tutorials further promote this particular aesthetic view, whether helpful or harmful, so the products recommended in the makeup tutorial could be promoted.

People are influenced by their surroundings more significantly than they thought. Think of some fashion trends decades ago, you may find it hard to fathom why these ugly things caught on. The secret is powerful word-of-mouth marketing. The public is inclined to believe what others believe, and at that time, people tended to label those trends as fashionable because all public words form an environment. On social media, the number of likes and comments, including the word count of comments, inform users whether such contents are reliable to the public or not. For example, some online stores in China make sales volumes visible to people who know less about the brand and offer coupons to consumers who provide positive comments to achieve the effect of brand publicity. Accordingly, the more people regard those contents as plausible, the larger the population in a circle grows. In this case, marketers succeed in the promotion. That is why establishing an atmosphere is an efficient way.

Live streaming is an excellent way to create an environment and unite a community. Compared with recorded videos, live streaming is more immediate, active and immersed because viewers can communicate with live streamers and see their authentic reactions. In this case, live streamers or influencers are the leaders in building a thriving climate. As preceding narration, live streamers belong to diverse interest circles, but they have something in common - setting the right mood. Since the pandemic, live streamers have become a hot vocation. The increasing number of stores have set specific positions on live streaming sales. Jiaqi Li, a Chinese live streamer from the beauty circle, was known for his powerful sales capability. His success, selling all the stock within a second, has everything to do with the stimulating atmosphere he established. After Watching his live streaming only once, the audience is destined to be impressed by his passion, elaborately introducing products, earnestly telling viewers why the products are worth purchasing and shouting at the screen to ask viewers to place orders. In addition, all the viewers or consumers contribute to forming this atmosphere because their active consuming behavior also prompt other viewers to conduct the same and become impulse buyers. Consequently, in product promotion, such an exciting air benefits the selling party.

Then, it comes to influencer marketing. Take Brandy Melville, a European clothing and fashion accessories brand that marks young women as its targeted consumers, as an example. This brand's marketing strategy shows how a company starts to build a specific environment based on different consumers' thought patterns, exposes their products to the targeted consumers, and finally leads them to purchase the products. Brandy Melville's marketing strategies in China and United States and the functions produced are different. Brandy Melville uses the controversy to lead people to debate and make itself inner remarkable. The controversy is derived from the social issues of gender inequality and gender stereotypes. Brandy Melville's "One fits the most" strategy calls for only offering one size, which fits girls from a 00-4 and "has left many girls feeling insecure, unworthy, and unattractive" [30]. This strengthens the gender stereotypes on women's physical appearance, assuming girls should be slim and then weed out bigger girls. SCIENMAG found that women's "feelings of anxiety and stress caused by COVID-19 were associated with a greater desire for thinness" [31] or body dissatisfaction. In China, during that time, for example, posts about "A4 waist", the women comparing the size of their waists to the width of an A4 sheet of paper, and "angular shoulder" prompted a further huge online backlash during the pandemic. The companies whose celebrities have these physical traits even pay to list these trends in high rank to be viewed by as most significant users, mainly Gen Z, as possible. In addition, China has already been found to be most likely to think body weight and shape are essential attributes in making a woman beautiful that 89% of Chinese accepted thinness as a body preference [32]. So Brandy Melville's strategy, which brings out "One fits the most" to targeted consumers, Gen Z, during this period in China, makes itself highly remarkable. Moreover, as Jonah Berger says, "just like many other animals, people care about hierarchy" [33], Chinese netizens were never tired of discussing BM employees' unfriendly attitudes as many were viewed as not fitting while those who are skinny and do fit in receive compliments from the employees, and be "identified with higher aesthetical prestige on social media" [34], could get more followers and even possible job offer -- this created a hierarchy among the girls [35]. Then, the inner remarkability and hierarchy provide social currency because it makes the people who share that they could fit in Brandy Melville's clothes look remarkable and good to others and feel insiders because of the scarcity and exclusivity-limiting size. This further evokes Gen Z's physiological arousal, especially high arousal. All of Brandy Melville's marketings in China not only evoke awe because of the admiration for unrealistic body image but also evokes anger and anxiety to the girls who fit the look and the firm which are "subject to the bitterness of people who have been made to feel bad about themselves" [36]. As Jonah Berger states, awe boosts the transmission and negative emotions, anger, and anxiety, "when used correctly, can also be a powerful driver of discussion" [37]. As a result, these emotions make the consumers talk, share and buy. Furthermore, Brandy Melville uses public visibility to drive products to catch on. As Jonah Berger states, people often imitate those around them. The sales assistant chosen by BM are usually identified as beautiful and popular, and many of them have already gained many followers. These young female sales assistants were asked and also volunteered to post how proud they are to be part-time in BM on social media because they "regard invitation to work for BM as a badge of honor, and a proof of one's popularity" [38]. This inspires the netizens, especially their followers, to talk about and buy BM because their posts inform that BM is good, which popular and beautiful girls like and admire. Finally, BM further gained positive word-of-mouth.

People in the United States have different values about beauty standard and developed thoughts about gender equality and gender stereotypes, so Brandy Melville focus on different strategies. According to Carmichael, people in the United States are not obsessed with slim bodies, and the United States falls below the global average in thinking that body weight and shape are essential attributes in making a woman beautiful. So Brandy Melville's strategies in China, such as paying for promoting trends to cause consumers' self-criticism on their appearance, damaging self-confidence and further strengthening gender stereotypes on physical appearance, do not work in the United States long term. Instead, Brandy Melville uses "minimalistic photo shoots and a laid back atmosphere to make their brand feel more down to earth and relatable to the teenagers that shop there" [39] and asks employees, who are usually directly out of the costumer pool, to perform as models and photographers for the instagram page and website. However, people in the United States gradually noticed that although BM is trying to be relatable to any normal Gen Z, this company only caters to a small portion of the population, further strengthening the pressures on women and increasing the possibility of social issue about gender stereotypes. While the overall attitude in China is "You should not complain just because you can not be one of them" [40], people in the United States have different responses. Unlike Chinese celebrities, who are usually paid to promote Brandy Melville or wear its clothes to show their slim body, and the ordinary people, who excuse this brand, people in the United States usually make the issues public and call for boycotts of this fashion brand. For example, a popular TikTok user, callijeanxo, revealed that Brandy Melville hires based on a certain look and the employees, or the imaged targeted consumers are skinny, tall and white. In addition, a netizen claims that the sizing led her to develop an eating disorder [41]. Moreover, groups of its former employees hope the brand and its executives will be exposed and shut down because this brand does not want to change with the shifting of beauty standards [42]. In addition, this brand is owned by men, "who actively and unashamedly profit off of the

insecurities of teenage girls, is deeply disgusting, unarguably sexist, and shows the damaging origins of the beauty expectations women are subject to" [43].

In the United States, Brandy Melville first gained positive word-of-mouth among young consumers. However, society and the consumers figure out the potential social issues hidden in this brand as soon as possible to prevent more girls and women from being pressured by gender stereotypes and gender inequality. Finally, Brandy Melville gained negative word-of-mouth and was criticized for riffing with racism, sexism, and antisemitism. In China, after revealing more social issues about gender inequality and stereotypes during the pandemic, more girls and women began to focus on women's rights and "body positivity has already sparked an open debate in Chinese social media". More people are "calling on women to say no to unrealistic body standards" [44], so Brandy Melville is expected to gradually gain negative word-of-mouth now.

The pandemic brought about specific climates similar to the one Brandy Melville started. During that period, people have experienced much quarantine time. As a serious social event that involved the whole society, this became a main theme of influencers on social media. To keep high-quality output, they were almost obliged to find something special. The fact that estranged from contacting with others face to face, many individuals lose the motivation to maintain their appearance was a just the one. Gaining weight which may give rise to poor body condition was the most prevalent phenomenon.

Table 2: Factors Gen Z considered before purchase before and after the pandemic.

According to a survey conducted 1,319 young people and the anthropometric data on weight and height, during the pandamic, though over 41% of the subjects reported a healthier diet, more than 1/3 of all subjects decreased physical exercised [45]. In view that weight is determined by both what they ate and how much they exercised, when the latter dwarfs the former, overweight prevailed. Influencers, as a sequel, began to focus on dealing with such health problems. The environment was built. A fad of losing weight caught on. Apart from fitness influencers' emerging, such as Will Liu mentioned above, fat-reducing food and sugar-free food hit the market. People's fever for this trend can be embodied by the popularity of antifat snacks and even junk food which have long been regarded as fattening foodstuff. Many influencers created outputs talking about such snacks. Regardless of whether they discuss the function of losing weight or the taste of the snacks, they are adding exposure of these products. A Chinese beverage brand called Genki Forest caught on for its claim of sucrose-free and low-fat is one successful example of outgrowth of this fad.

In the research, five factors Gen Z taking in account before consumption were ranked as practicality, price, appearance, word of mouth and friends' recommendation. The rank has kept the same after the pandamic, but the percent of each factor changes. Salient and noteworthy elements are the increased practicality, word-of-mouth and appearance concerns, which can be vindicated by the following example. In that multifarious resourses were not very accessible during quarantine time, cooking trend emerged. The electric appliance air fryers hit the market greatly. Famous for multi-function, air fryers were popular among Gen Z who favour exquisite devices, do not have a good commend of cooking and judge products chiefly by its word of mouth, but have to cook on their own if they are in quarantines. Besides, influencer marketing which can tremendously improve word of mouth played a momentous role in the publicity of air fryers. On social media, influencers recorded themselves making a multitude of delicious dishes or innovative desserts with an air fryer. Not saying a word about the appliance, viewers see its powerful function. Further exposure to it, Gen Z gradually generate the idea that owing an air fryer is chasing the fashion, or that an air fryer is a wide-use necessity. Their consumption behavior, consequently, formed.

According to the WHO (World Health Organization), the global prevalence of anxiety and depression has increased by 25% during the COVID-19 pandemic, and 90% of countries surveyed have included mental health and psychosocial support in their COVID-19 response plans.[46] One result of the research manifests that Gen Z's need for socializing dramatically increased during the pandamic, embodied by the fact that nearly half of all subjects present an increased consumption on social games, such as board games and live-action role-playing games. Gen Z's pursuit for sense of engagement further give popularity to LARP games. It can be inferred that during this special period, young people may think of a multiplayer game as a good way to enhance friendships and have fun. In China, the national government is aware of this trend and has taken efforts to encourage the development of such games, hoping to reduce social anxiety of the young. The encouragement can be embodied by the increasing number of social game-themed TV programs and the emergency of offline stores and online apps that specialized in social games.

3.2. Fan Economy Based on Trust

According to Kineta Hung, fan economy is "an operational mode that focuses on the customers’ emotional capital and leverages their loyalty towards a celebrity or brand to obtain economic and social benefits." And unlike the traditional economy, "consumers are taking a leading role in it" [19]. Idols have long dominated fan economy, for most of their fans love to display the fan identity via purchasing products endorsed by their idols. While since the boom of social media during the pandemic period, the number of influencers and live streamers has considerably increased. They become a strong force in fan economy. This paper will focus on the latter group of people.

In the research of 336 individuals from Gen Z, more than one third of them (36.9%) decreased in purchasing products by following celebrities. This is a comprehensive result of both inner factor- Gen Z's characteristics and outside factor- the era. Owning relatively abundant materials, Gen Z focus more on self-improvement and self-realization. They are positive, assertive and independent, so when it comes to star worship, they are destined to become more selective than the elderly generation, not idolizing someone easily. Besides, the cost of becoming famous is curtailed- all ordinary people can have a try, which shortens the distance between a notable person and his/her fans- they are more equal. Both the increased number of popular people and their fans' equal status give rise to a buyer's market. This fact signals that when it comes to famous figures' product promotion, Gen Z are rational. They may just consider the famous as sellers. Under this circumstance, the development of fan economy in the future relies on celebrities' setting up a trustworthy relationship with fans. To illustrate, if viewers trust a live streamer's insight of selecting products, they may be more willing to place the order on their channel when watching the live streaming.

Building this kind of relationship is not an easy job, for it calls for an emotional connection which is increasing with strengthened identification among groups [47]. fan economy loses its depth (the amount of products a group of followers buying from one celebrity's recommendation without much consideration), it does attain width (the number of follower communities of different celebrities) due to the increasing number of influencers. In other words, Gen Z, as followers, lack extreme loyalty to one notable person, but they are following plentiful notable persons, which actually improves the chance of Gen Z to pay for something via two specific ways. First of all, among the large following list, they are more likely to encounter items in need from their followings' outputs. The second situation occurred more frequently is that many individuals in the following list recommend the same products. As is mentioned above, the power of word of mouth takes effect.

A typical example is well-received evaluation videos. The contents of such videos are usually a compare of same kind products from different brands. Most people make these videos are small influencers who have fewer fans, many of which are ordinary people who take influencers as a part-time job. Though post-production of their videos may be plain and staightforward, Gen Z are actually more willing to trust them, thinking of them as an honest style of sharing feedbacks after consumption. Watching various evaluation videos before placing an order becomes a habit for Gen Z. Apart from small and daily products, such as cosmetics, snacks, and games, big deals, such as cars and houses have evalution videos. In China, the social media called Xiaohongshu is known for this kind of videos, and thus has been well welcomed in recent years. The research has shown that Xiaohongshu increases nearly 8% on usage frenquency among Gen Z.

4. Conclusion

With close research and analysis, this paper asserts that social media marketings, related to elements like social currency, emotion and public visibility, have formed or influenced Gen Z consumers' thoughts, values and behaviors, including consumption views and behaviors. These social media marketings collaborate with two categories of trending topics, social issues of gender inequality and stereotypes, and influencer marketing with live streaming, which stand out under the circumstances of economic recession, globally increased screen time and decreased physical activity among Gen Z. After utilizing collaborations to impact consumer Gen Z's thoughts, values and behaviors, marketers' products were also naturally related to these two extensively discussed trending topics among Gen Z, and then also widely discussed by this generation at the same time. Finally, during the pandemic, marketers gained word-of-mouth, either positive or negative. To be specific, marketers focus on Gen Z consumers during the pandemic because Gen Z is assumed to be the most active generation of social media users and leading participants in e-commerce, an arresting prospect in marketing -- it could be concluded from the research data and questionnaire that over half of 336 surveyed Gen Z claim an increase in social media usage after the outbreak of COVID-19 and nearly half of them report an increase on online shopping since the pandemic. As social media is the main platform for Gen Z to receive news and entertain like shopping, the transmission of social news, influencers and live streaming was facilitated by Gen Z. During the pandemic, the influences of social news, mainly about gender inequality and stereotype in this paper, and influencers, usually utilizing live streaming, reached an unprecedented height with the increased screen time and economic recession. Gen Z in China and United States were negatively affected by these social issues and their ideas. However, they become more critical at different paces as more social issues related to themselves are exposed during the pandemic. These brought about merchants' brand-new social media marketing strategies during the pandemic, and their products gained word-of-mouth, although it was not always positive. This research could warn society and marketers to utilize trending among Gen Z properly, instead of harming Gen Z, like strengthening body anxiety among Gen Z to promote their small-size cloth. This could work in the short term but be critiqued and lead to negative word of mouth, more importantly, cause irreversible adverse effects on some Gen Z.