在虛擬社群的環境下，社群成員因為對相同議題有共同興趣，因此很容易產生共同需求，使得集購活動日益普遍。線上集購本身也是種虛擬社群，其融合了交易、興趣與關係等虛擬社群特色。線上集購與一般購物差異在與其著重在與成員之間的互動，成員藉由參與團購活動建立彼此之間的角色與互動關係，而線上集購中最主要的角色為主購與團員，隨著交易情境的不同，成員角色也跟著變換。然而在不同的角色與互動關係上，例如：主購的開團數、募集數量、與團員的互動次數；團員的跟團數、與主購的互動次數；團員之間的共同跟團數等行為，是否會影響線上集購行為。
因此，本研究應用社會網絡分析法探討使用者在NeGoGo集購網上呈現的主購與團員、團員與團員間的網絡現象，並從中發掘其在線上團購的意義，以期從中找出可循的脈絡做為發展推薦系統上的基礎或行銷上的運用。
研究結果發現在主購與團員網絡中，主購的影響力較大，也較容易處於資訊傳遞的關鍵位置上。而在團員與團員網絡中，部分團員的影響力明顯地較大，這些團員容易影響其他團員來加入團購，而與其他團員同時跟團次數愈多時，也愈容易佔據資訊傳遞的關鍵位置。此外，本研究也找出中介程度較高的會員，針對這些會員宣傳團購相關資訊時，能較有效地達到宣傳效果。

In recent years, many virtual communities have thrived with the rapid development of Internet. In the environment of virtual community, through the information exchange, members realize that they often have similar demands. In the case of online group-buying, buyers who have a common interest in a certain product group together to collect their collective power and thus get price discounts from suppliers. Hence online group-buying comprehends the need of interest, relationship, and transaction of virtual community. We are questioning whether the group-buying have invisible community relationships embedded in members’ transaction activities.
The purpose of this study is by the use of social network analysis to investigate the relationships of the network between initiators and participants and between co-participants. In particular we propose some measures based on social network analysis to help us understand the meanings of relationships of online group-buying network.
According to the result of this study, we find the initiators have more power or resources to influence other members of the network between initiators and participants. And some active participants also have more power or resources to influence other participants of the network between co-participants. We also find the active initiators and participants would have more probability to occupy key positions of information flow.

Chapter 1. Introduction 1
1.1 Background 1
1.2 Research Motivation 3
1.3 Research Purpose 6
Chapter 2. Literature Review 7
2.1 Online Group-Buying 7
2.1.1 Online Group-Buying Definition 7
2.1.2 Online Group-Buying Model 7
2.1.3 Online Group-Buying Behavior 8
2.2 Virtual Community 9
2.2.1 Virtual Community Definition 9
2.2.2 Virtual Community Categorization 10
2.2.3 Involvement and Trust in Virtual Community 12
2.3 Social Network Analysis 13
2.3.1 Definition of Social Network Analysis 13
2.3.2 Categories of Social Network Relationship 13
2.3.3 Levels of Social Network Analysis 15
2.3.4 Measure of Social Network Analysis 16
Chapter 3. Conceptual Framework of Group-Buying Social Network 18
3.1 Group-Buying Social Network 18
3.2 Category of Group-Buying Social Network 21
3.2.1 Network of Initiators and Participants 21
3.2.2 Network of Co-Participants 22
Chapter 4. Research Methodology 24
4.1 Data Collection 24
4.2 Social Network Analysis Tool 27
Chapter 5. Data Analysis and Results 28
5.1 Descriptive Statistics 28
5.2 Network Analysis 29
5.2.1 Initiators and Participants Network 33
5.2.1.1 Centrality Analysis of Complete Network 33
5.2.1.2 Pearson’s Correlation Coefficient Analysis of Complete Network 38
5.2.1.3 Centrality Analysis of Ego Network 40
5.2.2 Co-participants Network 43
5.2.2.1 Centrality Analysis of Complete Network 44
5.2.2.2 Pearson’s Correlation Coefficient Analysis of Complete Network 48
5.2.2.3 Centrality Analysis of Ego Network 49
5.3 Discussion 52
Chapter 6. Conclusions 54
6.1 Empirical Findings and Applications 54
6.2 Limitation 54
6.3 Future Research 55
References 56

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