With the advancement of social media, online communities have become popular platforms wherein people can quickly post, comment, and collaborate [Hajli, 2014]. Social media create commercial value for firms. Given social media's commercial potential, it becomes vital to understand how consumers perceive these platforms as social commerce platforms. Social commerce is a new stream of e-commerce [Hajli, 2019]. In social commerce platforms, consumers rate, review, recommend and refer products and services to peers; they have been referred to social commerce constructs [Hajli, 2015]. Social commerce is also the primary foundation for sharing commerce, where consumers business with other consumers such as Uber and Airbnb. There are different drivers for social commerce. Electronic word of mouth [Goraya et al., 2019] persuades consumers to share their experiences and knowledge about products and services with peers on e-commerce platforms. Research shows social commerce platforms have great value for the firms and customers [Bazi, Hajli, Hajli, Shanmugam, & Lin, 2019; Hajli, Shanmugam, Papagiannidis, Zahay, & Richard, 2017; Lin, Wang, & Hajli, 2019; Tajvidi, Richard, Wang, & Hajli, 2020]. However, in these sharing platforms, consumers also have many concerns, such as privacy, information security, and trust [Hajli, 2018; Nadeem, Juntunen, Hajli, & Tajvidi, 2019]. Trust and privacy become essential aspects of social commerce platforms [Hajli, Shanmugam, Powell, & Love, 2015; Kong, Wang, Hajli, & Featherman, 2020; Nadeem, Juntunen, Shirazi, & Hajli, 2020; Nadeem, Khani, et al., 2020; Wang, Tajvidi, Lin, & Hajli, 2020]. As such, understanding the influence of consumers' perceptions of privacy and security in the creation of consumer trust that influences intended and actual use of social commerce platforms in purchase decisions becomes crucial. Therefore, in this special issue, we explore new perspectives, models, and research on the consumer reaction to and reliance on e-commerce systems and supply chains in the Covid-19 era. E-commerce systems and supply chains need to adapt to support increased activity, perhaps from less-knowledgeable consumer segments. This special issue, therefore, explores research into the evolving nature of social commerce systems. The first paper, entitled "the identification of ideal social media influencers: integrating the social capital, social exchange, and social learning theories." The authors argue that the biggest challenge in fostering social commerce is to stimulate social media influencers (SMIS) to create unboxing reviews of products and impact customers' attitudes and purchase intentions. This research integrated the social exchange and social capital theories to construct a model for investigating SMIS' willingness to create unboxing reviews. Besides, this study employed social learning theory to quantify word-of-mouth impact on customers' attitudes and purchase intentions. The results may help identify the motivations underlying SMIS's willingness to create unboxing reviews and the factors that influence customers' attitudes and purchase intentions. The second paper is entitled "comparing the impact of presentation format of consumer-generated reviews on shoppers' decisions in an online social commerce environment." This paper compares the impact of the presentation format of consumer-generated reviews on online shoppers' perceptions, attitudes, and purchase intentions within an online social commerce environment, using an integrated conceptual model that combined the technology acceptance model and media richness theory. They argue as a new stream in e-commerce, e-marketplaces are increasingly evolving into social commerce platforms that allow online shoppers to co-create brand-specific content to help their peers in the purchase decision-making process [Hajli, 2015]. In this research presentation format of customer-generated reviews is a between-subjects factor, with 339 online shoppers participating in an online survey. The results indicate that technology acceptance and media richness factors influence shoppers' acceptance of reviews and purchase intentions. Their findings discuss the implications for social commerce research, theory, and practice and make several useful future research recommendations. The third paper is entitled "brand value co-creation in the social commerce era: empirical evidence from Iran." The authors argue that the upward trend in social media use has transformed e-commerce by adding social support and information sharing features, resulting in social commerce. In this study, the authors test a framework that examines firms' e-commerce opportunities from a branding perspective. With a survey of Iranian consumers, they use SEM-PLS to analyse the data. Their results provide new insights for a strategic approach to social media use concerning its value co-creation objective. The findings of this research confirm the research model and emphasise the importance of social commerce constructs, social support, and relationship quality in brand value co-creation. The fourth paper is entitled "stay home and shop together." Drawing on Bales' Interaction Process Analysis and research on medial richness and consumer shopping behaviours, the authors propose a conceptual framework of social interactions in collaborative online shopping. Authors postulate antecedents and outcomes of the task and socio-emotional communication between co-shoppers in the collaborative online shopping context and delineate the moderating impact of shopping group structure. Arguing for the essential role of within-shopper communication in collaborative online shopping, the authors distinguish two types of communication activities: task-oriented and socio-emotional, and propose the shopping group structure typology. Authors then developed a conceptual framework of social interactions where antecedents and consequences of these communication activities are theorised. Finally, the fifth paper is entitled "The Role of Self-Congruence, Marketing Models, and Product Conspicuousness in College Students' Online Cosmetics Shopping." The study's primary aim is to explore the influence of customers' self-congruence (SC) and brand identification (BI) on purchase intention (PI). The study collected data from 246 college students who had purchased open-shelf cosmetics online. According to the research results, when college students think that the brand's personality can reflect their actual appearance or reflect the ideal appearance they want to achieve, they can effectively induce consumers' PIs. Also, the study shows that if the brand's identification and individual's SC are higher, the easier it is to be included in the individual's self-concept, which will result in purchase intention for the brand. On the other hand, because consumers will use consumer behaviour to convey information about their self-concept to others, they prefer brands and products with high self-image consistency.