「同溫層」是近年社群媒體的熱門詞彙,這個詞彙的背後指涉什麼概念 值得進一步探討。我們預設每個網路社群中都有同溫層的存在,但由於其組 成要素不同而使每個社群的態樣有所差異。作者從媒體文本萃取出最常出現 的概念,再根據相關理論內涵,建構以下四項特徵概念:成員同質性、意見 一致性、社群互動性和資訊邊界性等四項指標。 本研究以關注婚姻平權的臉書粉絲專頁為研究場域,以滾雪球的方式找 出關注婚姻平權的粉專,使用上述四個指標進行分群,最終分出五類粉專。 整體而言,在成員同質性、意見一致性和社群互動性的表現上是挺同團體數 值較高,表示其內部互動的人與狀況是較同質與熱烈的,相反意見的爭吵較 少。而反同團體則是資訊的邊界性較高,所引用的來源極度相似。進一步分 群觀察,群 A 的粉專不常分享外來的資訊,為專門產製內容的一群;群 B 的 粉專內部討論意見最不一致,是議題中的戰場;群 C 的粉專成員較相似、意 見高一致以及互動較頻繁,在議題中最能取暖;群 D 的粉專是議題的邊陲群 體;群 E 的粉專是陣營的中堅分子,有著一定的規模和流動人數的活絡粉專 群。
本研究梳理同溫層的概念並操作化其定義,這些指標及分析方法將可用 於未來研究者觀察網路社群使用者的意見如何配置以及訊息如何流動。

關鍵詞:網路同溫層、社群媒體、臉書、婚姻平權 

 "Stratosphere" has become a popular term on social network sites in recent years. This thesis focuses on the concept which "Stratosphere" refers to and on the related phenomena which are deemed important by the previous researchers. We presume that "Stratosphere" exists in every online community while different components of each community make their types different. This thesis defines the characteristics of "Stratosphere" by how media represent it and combine them with theories/concepts including virtual community, group think, and echo chamber effect. After that, we put forward four indicators to describe "Stratosphere", namely: member homogeneity, opinion consistency, community interactivity and information boundary. At the stage of data collection, we apply snowball sampling to gather Facebook fanpages which pay attention to the topic of same-sex marriage in Taiwan from March 1 to June 30, 2017. Then, we calculate the value of each indicator of each fanpage and divide them into five clusters which stand for five types of online community. In general, fanpages which support same-sex marriage get higher scores in member homogeneity, opinion consistency and community interactivity. It means that opposite opinions seldom appear in their discussion space. Fanpages which are against same-sex marriage have better performance in information boundary, meaning that they concentrate on sharing similar information. Further, this study divides fanpages into five clusters by the characteristics of “Stratosphere”. Fanpages of Cluster A rarely share information from the outside as their contents are mainly produced by themselves. Cluster B is characterized by the fact that different opinions frequently show up in their discussion space. People in Cluster C are more similar, share consistent opinions and interact frequently, showing that these fanpages provide the best space for empathy seeking. Fanpages of Cluster D have only a few users and are the marginal groups of this issue. Lastly, fanpages of Cluster E are the ones with numerous active users and many are important opinion leaders on the issue. In sum, this thesis is to make the concept of "Stratosphere" operable and focus on different orientations of "warmness". With a case study of same-sex marriage, researchers define four characteristics and five types of community of "Stratosphere". Furthermore, the indicators and features of the types in this study may help subsequent research understand how different kinds of user opinion distribute and the information flow on social network site.