社交網絡與微網誌在日常生活應用愈見普及，傳統仰賴大眾媒介傳送商品訊息的公關與行銷概念，也在成本預算與執行成效受到挑戰。而從網路溝通發展出來的「口碑行銷」和「病毒行銷」，除能降低成本縮短時間，更可有效與目標公眾產生連結。然而兩者共同焦點，皆隱然指向行銷操作成功與否，關鍵在於少數主動者願意透過人際關係網絡傳送訊息，因此如何策動這群「影響者」擴散行銷訊息，乃成為「影響力行銷」核心。為深化理論思考，本研究從「兩級傳播」的「意見領袖」概念出發，扣連訊息流通過程的「親身影響」，以及「口碑」和「病毒」等行銷操作，來釐清「影響者」的角色意涵，進而將線性的影響力行銷，轉化為環狀思考模式。另外並透過實際案例，嘗試擴充思考層次，亦即「影響者」除了是掌握和散佈資訊能力較佳的個體，也可能是科技衍生的虛擬人物，雖不具真實身份，但同樣卻具有影響力。

As social media network and micro blogging are getting more and more popular in our daily life, the traditional public relations and marketing ideas of relying on mass media sending information are challenged regarding cost, budget and execution possibility. “Word-of-mouth marketing” and “virus marketing”, stemmed from Internet Communication, can not only effectively reduce the campaign time and cost, but also efficiently contact the target audiences. Both of them guide us to the key of successful marketing—the influencers, who are willing to send out information thorough personal network. Therefore, how to motivate these influencers to spread information leads to the core of Influencer Marketing. With regard to theory construction, this research reviewed the theories of “two-step flow of communication” and “opinion leaders”, and then further linked the concepts of the “personal influence,” word-of-mouth, and virus marketing to clarify the roles of influencers, extending the liner model of influencer marketing to the circular model of influencer marketing. This research also brought in real cases to demonstrate how the virtual characters can be categorized as a type of influencers.