Web2.0時代來臨後，社群媒體成為選戰期間政治傳播的重要管道。本研究探討在2012年台灣總統大選期間，社群媒體「臉書」的使用對選民的政治參與行為，特別是投票行為，究竟會產生什麼樣的影響？使用社群媒體的動機與政治參與行為是什麼樣的關係？而不同的使用動機將會如何影響選民的投票行為？研究結果發現，社群媒體使用率越高、越關注社群媒體選舉訊息的選民，無論是透過候選人的社群媒體或者是個人社群媒體，皆越有可能參與線上或線下的政治活動，如參與線上選舉議題討論、連署或捐款、遊行等。而個人社群媒體的選舉訊息使用率越高，投票可能性也越高，但候選人社群媒體的使用率或關注程度，卻與投票可能性無關。而社群示好行為則證實與投票可能性呈現正相關。在社群媒體盛行的時代中，選民越常在社群媒體上與候選人為友、加入其粉絲團或者按讚，表現出類「政治迷文化」的行為，越有可能去投票。此外，社群媒體表達自我或互動動機、政治資訊需求動機以及娛樂需求動機，皆與政治參與行為有正相關，不過三種動機與投票可能性均無相關。而政治傾向為泛藍的社群媒體使用者在此次選舉中較有可能去投票。

In the Web2.0 era, social media have become important channels of political communication during elections. Using Facebook as a case study, this study intends to investigate the impacts of uses of social media on voters' political participation, especially voting likelihood, during the 2012 Taiwan presidential election. Moreover, this study considers whether the motivations of using social media would affect social media's effects on political participation. Results confirmed the positive relationship between uses of social media and voters' political participation. The more voters use and pay attention to social media, the higher the frequency of their political participation behaviors, such as online discussion on campaign issues, online petitions, and offline protests, and donations. Regarding voting likelihood in political participation, the uses of personal social media for campaigning information do increase the voting possibility. Voters' befriending behaviors towards candidates are also found to be related to their voting likelihood. However, among all the variables, only voters' political inclinations are able to predict voting likelihood.