網際網路的蓬勃發展，不僅改變人們傳播的方式，也改變了訊息流通的模式，透過e-mail，網路使用者可以傳遞任何訊息到任何地方，其中當然也包括了「網路謠言」的傳佈。過去相關的研究多把網路謠言的研究重心擺在商業傳播的領域，卻少有人把相同的注意力放在政治傳播的競技場。 本文將首度研究網路政治謠言的可信度，以及其轉寄行為，除了找出影響可信度、轉寄行為的可能預測因子，例如網路使用、網路電子郵件的暴露度、政治參與以及人口變項等等，並進一步去了解網路謠言可信度與其轉寄行為之間的關係。除此之外，本研究引用了「認知不合諧」理論，嘗試去解釋轉寄行為的背景因素。 「線上調查法」乃是本研究所採行之研究方法。本研究在2004年臺灣總統大選投票日後的三週內，也就是「319槍擊疑雲」電子郵件在網際網路大量流竄的期間，透過網路問卷，調查該類電子郵件的可信度以及其轉寄行為。 研究結果顯示，「319槍擊疑雲」電子郵件的可信度並不高。年紀較大、教育程度越低、政黨支持度較弱以及對該類郵件越注意者，傾向認為該類郵件具有較高的可信度。而有超過一成的網友，曾經轉寄該類郵件給親友。越認為該類郵件可信，越會有轉寄的動作。另外，泛藍支持者又比泛綠支持者更容易產生轉寄的行為。

The Internet has changed the way of communication and message circulation. Through emails, Internet users can transmit any message, including rumors, to anywhere as they wish. Many studies paid attentions to the Internet rumors that took places in the field of business. However, few focused on the same phenomenon in political arena. This study aims to discover the creadibility of rumor emails in the field of political communication, and tries to determine if the factors such as Internet usage, email exposure, political interest, and demographic variables have any effect on the credibility. In addition, this study also tries to explore the connections between credibility and rumor forwarding. The study is based on the online survey designed to attract politically interested web users. The survey was posted on the web in a span of three weeks after the 2004 Taiwan Presidential Election when the 319-assassination-related rumor emails roamed the Internet. The respondents were asked to evaluate the credibility of the rumor emails and report their behaviors of forwarding the emails. The result shows that the credibility of the 319 rumor emails is not high. The older, lower-educated users and those who have lower party-strength and lower interests in politics tended to rate the emails more credible. Among all research participants, more than 10% had forwarded rumor emails to their friends. The result also suggests that the more credible they thought the mails to be, the more likely they would forward the mails. In addition, the users who support for Pan-Blue were more likely than Pan-Green to have tendency to forward the rumor emails.