Abstract
One growing use of computer-based communication media is for gathering people to initiate or sustain social events, but online participation in an event does not always translate to offline attendance. This thesis investigates whether and how the gap exists between online and offline forms of participation. The thesis consists of two studies: We first look at how people handle online event invitations and what influences their online and offline participation by interview. Then we conduct an experiment to further examine the role of a few crucial factors found in interviews, including social tie strength and interface factors. The results illuminate the sophisticated nature of the mechanisms that affect participation and provide new understanding on the effects SNS features have on people’s online responses and offline attendance. Furthermore, this thesis demonstrates that improving interface design has the potential to bridge virtual and real attendance.