Unveiling the Power of Influencer Marketing: A Systematic review of Influencer Marketing Antecedents, Outcomes, Theoretical Framework and the Future research Directions

Influencer marketing (IM) has become increasingly common in business strategies as a result of the exponential growth in popularity of social media influencers (SMIs) over the past several years. Despite the growing attention of academics and professionals, the scholarly work that has resulted is still inconsistent


Introduction
Influencer marketing is a form of marketing that uses social media influencers to market a product or service to their followers. An influencer is someone who is widely followed on social media and is considered an expert or authority in their field. When influencers recommend products or services, their followers are more likely to believe their recommendations and take action (Masuda et al., 2022). Influencer marketing encourages social media users to engage with sponsored content (Hughes et al., 2019). Outcome variables include cognitive, emotional, and behavioural involvement (Hollebeek et al., 2014). Likes, comments, and reposts can indicate social media participation (Malhotra et al., 2013). Reposting content shows a deeper commitment because consumers choose to share it with their networks (Malhotra et al., 2013). This participation influences other potential customers and improves firm success (Pansari et al., 2017).
Influencers are people with a large following who are trusted tastemakers in specialized areas (Veirman et al., 2017). According to Brown et al. (2008), influencers are customers who can directly affect their following. Influencers are content creators and specialists who use social media to influence their networks (Ge et al., 2018;Hearn et al., 2016). Influencers' advice is trusted (Djafarova et al., 2017;Schouten, 2019). Contracting with influencers can reduce brand risk, increase brand exposure, and provide essential information to target audiences (Chatterjee, 2011;Carter, 2016). Their messages are also digital (Evans et al., 2017;Hearn, 2016). Internet and mobile technology have changed consumer behaviour. Consumers frequently browse user reviews before buying online. Sharing visual content is key to effective communication. Travel companies are cooperating with SM influencers or content writers to efficiently communicate with consumers and promote their products and services. Influencers can spread companies' messages to new audiences (Yetimoğlu et al., 2020). This study will answer the following influencer marketing retrospective research questions.

RQ1.How does influencer marketing affect customer brand awareness?
RQ2. How do influencers affect consumer behaviour and purchasing decisions in influencer marketing?
RQ3. How can influencer marketing engage and activate audiences more than traditional advertising?
RQ4. How does influencer marketing affect customer views and brand loyalty long-term? RQ5. What are the potential future research directions in the field of influencer marketing?
Influencer marketing is getting increasingly popular, but its long-term effects on customer behaviour and brand loyalty are unknown. Despite various research on influencer endorsements' immediate effects on customer purchasing decisions, these marketing initiatives' long-term effects are unknown.
Micro-influencers' authenticity and reputation are compared to macro-influencers by customers. Does micro-influencer authenticity boost consumer trust, engagement, and buy intent? Long-term Relationships and Brand Advocacy: Are micro-influencers more likely than macro-influencers to form lasting bonds with their followers and promote their brands? How do these relationships affect brand loyalty and customer engagement? How do microinfluencers generate more comments, shares, and direct interactions than macro-influencers? Interactivity changes brand-consumer interactions and perception. How do you analyse microinfluencer marketing? How can marketers measure the impact of micro-influencers on consumer behaviour, brand recognition, and other outcomes? These study gaps can reveal micro-influencer marketing's unique benefits and effects (Leung et al., 2022).
The study focuses on influencers in general, but there's a research gap related to the comparative benefits and dynamics of micro-influencers and macro-influencers. We have highlighted questions about micro-influencers' authenticity, ability to build lasting bonds with followers, and their impact on brand loyalty and engagement. Exploring these aspects could provide insights into whether micro-influencers are more effective than macro-influencers in certain scenarios and shed light on the unique advantages they bring to influencer marketing campaigns.

Searching Strategy
Empirical studies made up 45 of the review's papers. IM literature lacks conceptual contributions despite a wealth of data-driven research. Knowledge development requires integrated viewpoints and innovative theories (MacInnis, 2011). Future research should broaden this field's theoretical terrain. These studies used mostly qualitative data collection methods. Quantitative theory testing was prioritized over qualitative model construction, requiring further study.

Literature Review
Influencers can sway their audience's purchasing due to their credibility. (De Veirman et al., 2017). They admire a dependable taster. Influencers are advocating things to their followers and beyond as companies reject traditional advertising (De Veirman et al., 2017). Previous research studied how influencer posts' popular language affects customers' ability to recognize advertising due to Instagram's disclosure advertising. User-friendly (Evans et al., 2017). Customers trust transparency. 1,500-150,000 micronutrient-exposed users are more aware and like marketed products. A micro-influencer's "disclosure" hashtag increases sales (Kay et al., 2020;Britt, 2020). Zhang et al. (2016) User content matching affects message retransmission and content, according to research. The commercial nature of the message or content also lowers credibility and confidence in the influencer (Martínez-López et al., 2020). Transparency increases vloggers' and influencers' credibility, making endorsements more credible. Lifestyle vloggers are trusted and influential (Chapple et al., 2017). When linked to alcohol marketing, the discovery garnered less likes and comments (Zhang et al., 2016;Hendriks, 2020). Previous studies found no difference between disclosure and kid food marketing. According to Coates et al. (2019), SMI success depends on varied attitude. Kimet al. (2020) found that product attitude increases when influencers and products match. Product attitude was also linked to sponsorship declaration.Most studies imply that additional social media followers improve brand or influencer performance. Some studies judge influencers and social media accounts by how many likes a post gets relative to its prospective audience. They also found that high and low likes-to-followers' ratios hurt social media marketing and lower power perceptions (Vries, 2019).
Influencer marketing is cheaper and more relatable than celebrity marketing, so marketers are using it more. Influencers are more trustworthy and optimistic about the proposed firm than celebrities (Jin et al., 2019). Marketing professionals use influencers rather than celebrities to determine purchasing intents (Trivedi et al., 2020). Social media's effects on advertising and marketing are uncertain despite their growing relevance. Advertising experts were surveyed on social media's changing impact on marketing. They found that advertising experts believe influencer marketing is a growing and popular topic, but a lack of direction and clarity can limit its efficacy (Childers et al., 2019). According to several experts, the audience is sceptical of influencers, particularly cosmetics specialists, and rarely sees the message as true. Beauty Instagram followers are more likely to trust influencers after a positive engagement (Konstantopoulou et al., 2019).

Methodology 3.1 Data Selection
We discovered 570 articles from Scopus, Web of Science (WOS), and EBSCO. We collected 200 Scopus, 220 Web of Science, and 150 EBSCO items. Refining with Excel Software ensured accuracy. Most articles were neglected for three reasons. First, we removed non-topical articles. Second, duplicate articles abounded. Finally, we ignored influencer marketing publications that did not contribute to learning. After refining the articles, we collected 30 Scopus, 10 EBSCOS, and 5 WOS papers. Finally, we reviewed 45 refined articles to confirm they fulfilled our criteria.

Data Extraction
Influencer marketing literature guidelines were followed. Our main objectives were to review current research and find new avenues to explore in this dynamic sector. We set study parameters using a thorough influencer marketing definition. Scopus, WOS, and EBSCO search for relevant peer-reviewed publications. These databases supplied influencer marketing insights and articles that fulfilled our study criteria. We carefully picked articles for review. This provided consistency and high-quality article selection. Publication date, study technique, and relevancy were assessed. This helped us find influencer marketing publications for our study.

Data Protocol
We wanted to educate people about influencer marketing and its commercial impact. We organize a search in Scopus, Web of Science, and EBSCO using search operators related to influencer marketing, celebrities, e-communications pathways in online buying, the innovative marketing technique, and proposed conceptual models. We included relevant papers from 2014-2022. We searched just English-language articles for consistency.  The essay concludes that influencer marketing may be unethical and should be avoided or utilized sparingly in the healthcare industry, even though it is legal with some constraints. Influencer marketing should be legal and moral.

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I. Yfantidou Quantitative 2021 Influencer Marketing in the Make-up Industry.
The study focused on the many actors and e-communication channels that shape online shopping. E-communication tactics including CSR, peer reviews, and expert opinion were used to study foreign clients' online purchase intent antecedents.  Increased Brand Awareness: Consumers' knowledge with the brand can influence their purchase decisions. Positive experiences, effective communication, consistent branding, and favourable associations can improve image. Improved image builds confidence and credibility. Customer Trust: Consistently delivering promises, transparent corporate procedures, reliable customer service, and great customer experiences earn it. Long-term consumer connections require trust. Customer loyalty is a brand's customers' allegiance, recurring purchases, and emotional connection . Market Insight: Market insight is a thorough understanding of market dynamics, consumer preferences, trends, and competition. Customer Feedback: Customer feedback includes customer thoughts, suggestions, and evaluations of a product, service, or brand. Competitive Advantage: A brand or organization's distinctive traits, talents, or tactics offer it a market edge. Brand Advocacy: Brand advocates are customers who willingly promote, endorse, or recommend a brand. Cross Promotion: Two or more brands or entities collaborate to promote each other's products or services. Brand Strategy: A brand's long-term plan to achieve commercial goals and build a distinct and desired brand identity is its brand strategy.

Result
This article's contribution to marketing theory and practice deserves discussion. (Kim et al., 2019) also expands consumer imitation of influencers. Consumer research mimicry, based on social learning theory, also addresses the need for more social SMI research (Vrontis et al., 2021). WOM intentions and buy intents function nicely together in the • Is exposure to influencer content associated with negative emotions like jealousy, worry, or self-harm?
• How much do influential people encourage materialistic values? Does exposure to influencer content encourage followers to have materialistic values?
• Longitudinal survey research may be used to assess the link between exposure to influencer contents and bad health as well as the growth of materialistic ideals.
• Content studies can look at how social media influencers promote materialistic (and other) ideals.
• Experimental research can look at how exposure to influencer content affects mental health.

What function do social activism influencers serve?
• How do influencers react to social and political issues?
• How much interaction are these postings getting? How are those materials being received by readers?
• How have these communications affected public opinion?
•You can conduct experimental studies and surveys to determine how these messages affect public opinion.
What impact does influencer marketing have on young audiences, and how?
• What purpose do influences serve in children's and adolescents' lives? How are they regarded as role models and inspirations? How do they contribute to someone's sense of self?How susceptible are kids to the information in influences?
• What processes underlie the effectiveness of sponsored influence materials?
• How can we enable kids to manage influencer content more critically?
•Focus groups and in-depth interviews can be used to investigate the significance of influences in young people's life. suggested approach. Later, SMI Research's lean customer wellness idea ensures follower wellness. Marketers benefit from this model. Brands everywhere are embracing influencer marketing. Selecting an influencer is difficult. Because knowing which influencers generate consumer mimicry simplifies the decision process.
Marketers and firms' influencer marketing strategies benefit. Consumer well-being also makes them think twice about working with SMI. Marketers must protect consumers. Influencers care about their fans and shun excessive consumerism. Governments and regulators are stirring up influencer marketing to cause unintended repercussions. Persuasion scholarship and theory may increase . Social media companies and national advertising agencies have issued guidelines requiring influencers to declare any product promotion incentives (ASA, 2019). But the big question is: does putting a company logo or the hashtags "#ad" or "#sponsored" hurt an influencer's reputation as an independent content creator? Audrezet et al. (2020) believe clear authenticity is essential, but empirical testing is needed.
By examining the nascent field of influencer marketing, Kim et al. (2019) study considerably advances marketing theory and practise. The study investigates the social learning theory-based phenomena of consumer imitation of influencers. As noted in the study of Vrontis et al. (2021), this investigation highlights the need for more research in the area of social media influencers (SMIs). A comprehensive viewpoint is provided by the study's integration of word-of-mouth (WOM) intents and purchase intentions when they work together inside the suggested framework (Iqbal et al., 2022). Further highlighting the significance of follower wellbeing in this context is the adoption of lean customer wellness concepts in SMI research.

Conclusion
A theoretical model was created to understand influencer marketing's effects. Despite industry accolades, influencer marketing has not progressed. Vertical video (IGTV on Instagram) and experiential marketing are important in interactive advertising's everchanging landscape. The future involves studying influencer marketing's effects on consumers and interactive platforms as well as the boundary conditions and mechanisms that affect brand growth and consumer behaviour. It is complex. This article examined why youth consume content and follow influencers. Empirical findings list social media influencer marketing, buy intention, customer behaviour, inspiration, and others.
In the Internet age, unaffiliated third parties use blogs, tweets, and other social media to influence audience impressions (Freberg et al. 2011). By writing product reviews, making how-to videos, hosting competitions, and posting product photos (Bernitter, Verlegh, and Smit 2016). Influencers improve their storytelling, filmmaking, and photography talents. The Internet's scalability and rapid diffusion allow these influencers to quickly gain cultural capital and fame (McQuarie, Miller, and Phillips 2013).

Practical Implication
This work has theoretical and practical effects. Synthesizing existing material helps marketers comprehend influencer marketing (IM) in social media ecosystems. Our integrative framework guides marketing professionals in designing effective IM campaigns and maximizing social media influencers' marketing efficacy.
SMIs have strong relationships with their followers and are considered experts in the campaign's topic, therefore several studies recommend working with them instead of celebrities with millions of followers . Popularity may not necessarily influence purchases. However, knowledge and relationships alone cannot achieve the desired goals. Influencers must be identifiable, authentic, and aesthetically consistent to succeed in IM marketing (Argyris et al., 2020). Consider the influencer's fit with the brand or product when launching a campaign. Communicatively successful and engaging product endorsements must reflect the influencer's lifestyle and consumption patterns (Silva et al., 2020).
Influencers who support each campaign should collaborate with marketers. A fashion company may partner with a SMI that offers knowledge and visually engaging content to boost product acceptability. However, a SMI can help the company boost business initiative coverage. This SMI will share high-quality, amusing knowledge. Allowing SMIs to develop brand-related content on their own encourages creativity, authenticity, realism, audience engagement, and business goals. Casaló et al. (2018) and Munnukka et al. (2019) say this adaptability is important for influencer-brand collaboration to work.

Implications and Limitations
The research study has numerous constraints. First, the research's contributing factors-like followers' persuasive talents and advertising literacy-have improved our understanding of influencer marketing's processes. The second survey question analysed social media influencers and user trust in their branded material. Influencers' message techniques and content vary across social media platforms, hence user views about these postings may vary too. SNS influencer marketing study could help firms connect with target audiences on this channel.
The current study's unanticipated findings-influencers' unreliability hurting brand awareness and buy intentions-need further study. Although we provided in-depth information about social media influencers and influencer marketing, future research may want to assess participants' understanding of the concept. Cultural influences on social media should also be studied. Future research may additionally examine media channel affordance, receiver motives and personalities, and message and source characteristics.

Upcoming Trends and Future Research
Metadata contained in social content helps with evaluation data (Martín-Llaguno et al., 2022). The context is derived of previous references to the influencer and its value behaviour and problem intersection, derived theory The early pioneering work of Katz (1957). Social influencers are stars and the difference between the two categories is who retweets who, which provides evidence of how information flows on Twitter. There are significant differences between Greta Thunberg and Bill Gates. The latter wants to create positive images of altruism related to the subject, while the first reflects the image of the social activity As Satell (2014) notes, "…if you want things to spread, forget about special people with "rare qualities", i.e., influencers to motivate those they want to motivate.
This study contributes to the study of the mechanisms leading to successful lobbying marketing campaigns. Current scholarship has shown the benefits of using influencers, as with purchase intentions, the persuasiveness of the message sent improved or improved attitudes towards the brand (see Djafarova and Rushworth, 2017;Lou & Yuan, 2019;Xiao et al., 2018). Other work has focused on trust in both influencers and influencers their messages (e.g., Djafarova & Rushworth, 2017;Jin & Phua, 2014;De Veirman et al., 2017) or about the potential negative effects of disclosure and business intentions influence influencer marketing (e.g. Shan et al., 2019;Sokolova and Kefi, 2020;Stubb et al., 2019).