過去已知消費者使用不同社群媒體的動機，但不了解消費者在每個購買決策過程使用不同社群媒體的需求與動機，也不清楚在不同決策階段何種社群媒體最適用。因此本研究針對18 – 34歲的消費者在評估階段與分享階段使用Facebook、Instagram和YouTube的預期需求滿足進行研究，並透過區位理論比較兩購買決策階段中，三種社群媒體在不同預期需求滿足的滿足程度（區位寬度）、媒體間的競爭狀況（區位重疊度）、媒體優勢性（區位優勢）以及整體競爭狀態。
　　　本研究利用調查法蒐集了430份有效樣本，研究結果發現消費者在評估階段有「獲得評論需求」、「休閒娛樂需求」和「資訊分享需求」，在分享階段有「評論娛樂需求」和「習慣分享需求」。比較評估階段媒體競爭狀況，YouTube在「獲得評論需求」和「休閒娛樂需求」皆有可能取代Facebook和Instagram，而Instagram則有可能取代Facebook，但三者在「資訊分享需求」為互相競爭關係；比較分享階段，YouTube在「評論娛樂需求」中有可能取代Facebook和Instagram，但Facebook與Instagram則互相競爭狀態，但在「習慣分享需求」中，Facebook有可能取代Instagram，Instagram則有可能取代YouTube，但Facebook與YouTube呈現互相競爭的狀態。

　　　The motivations of consumers to use different social media has been researched in the past, but the needs and motivations of consumers to use different social media in each stage of customer decision journey are not been found, and it is not clear which social media is the most appropriate at different stages. This study focuses on considering the needs of consumers aged 18 to 34 who use Facebook, Instagram and YouTube in the evaluation stage and sharing stage, and compares the consumer's satisfaction (Niche Breadth), the competition between media (Niche Overlap), the media superiority (Niche Superiority) and the overall competition through the Niche Theory.
　　　Collected 430 web questionnaires, the finding of this study shows that consumers have the needs for "obtaining comments", "leisure entertainment" and "information sharing" in the evaluation stage, while in the sharing stage, they have the needs for "comment entertainment" and "habitual sharing". Comparing the competitive states of evaluation stage, YouTube may replace Facebook and Instagram in "obtaining comments needs" and "obtaining comments needs", while Instagram is likely to replace Facebook, but the three are competing in "information sharing needs"; comparing the sharing stage, YouTube may also replace Facebook and Instagram in "comment entertainment needs", but Facebook and Instagram compete with each other. However, in "habitual sharing needs", Facebook may replace Instagram and Instagram may replace YouTube, but Facebook and YouTube may compete with each other.

中文部分
〈2019台灣網路報告〉（2019）。《財團法人台灣網路資訊中心》。取自 https://report.twnic.tw/2019/assets/download/TWNIC_TaiwanInternetReport_2019_CH.pdf。
王嵩音（2007）。〈網路使用之態度、動機與影響〉。《資訊社會研究》，12，57–85。取自http://www.nhu.edu.tw/~society/jccic/12/fu/12-03.pdf。
汪志堅、陳翔、江義平、江維彬（2013）。〈Facebook社交網站使用因素之量表發展與驗證〉。《電子商務學報》，15，319–351。https://doi.org/10.6188/JEB.2013.15(3).01。
李岳昇、王嵩音（2015）。〈印刷雜誌、數位雜誌與行動數位雜誌之市場區位理論分析〉。《資訊社會學研究》，28，35–65。https://doi.org/10.29843/JCCIS.201501_(28).0002。
邱皓政（2010）。《量化硏究與統計分析 : SPSS(PASW)資料分析範例（五版）》。臺北市：五南圖書。
〈品牌影響力調查 Most Influential Brands〉（2018）。《Ipsos、商業周刊》。取自https://www.ipsos.com/sites/default/files/ct/publication/documents/2018-01/n042_mkt_millennials_and_the_impact_of_social_brand_perception.pdf。
〈消費歷程中不容小覷的影響力 YouTube造就成效行銷新勢力 (上) 〉（2019）。《台北數位集團》。取自https://index.taipeiads.com/NewsData.php?oid=4。
區谷怡（2016）。O2O消費的使用與滿足和科技接受整合模式——以線上買票，線下觀影為例。國立政治大學傳播學院傳播碩士學位學程碩士論文，台北市。 取自https://hdl.handle.net/11296/2666b5
郭貞、黃振家（2002）。〈以區位分析比較網路、型錄、與商店做為購物管道之競爭優勢：一個跨年比較〉。《新聞學研究》，72，1–26。取自http://www.airitilibrary.com.autorpa.lib.nccu.edu.tw/Publication/alDetailedMesh?DocID=10161007-200207-201305130013-201305130013-1-26。
黃品慈、李秀珠（2013）。〈不同類型 IPTV 之市場競爭：從區位理論檢視PPStream、土豆網與 Youtube 之競爭〉。《中華傳播學刊》，207–241。https://doi.org/10.6195/cjcr.2013.24.06。
楊安琪（2018年9月14日）。〈YouTube 影音勢力全面啟動！國際年度盛會YouTube FanFest 蓄勢待發〉。《TechNews科技新報》。取自https://technews.tw/2018/09/14/youtube-pulse-and-youtube-fanfest/。
詹子君（2015）。《從「區位理論」探討線上新聞平台─ Yahoo! 奇摩、Facebook 與LINE─ 之間的情形》。交通大學傳播研究所碩士論文。取自「全國博碩士論文資訊網」https://hdl.handle.net/11296/f9tue2。
萬文隆、林淑芬（2004）。〈深度訪談在質性研究中的應用〉。《生活科技教育》，37，17–23。https://doi.org/10.6232/LTE.2004.37(4).4。
《維基百科》區位論。取自https://zh.wikipedia.org/wiki/%E5%8C%BA%E4%BD%8D%E8%AE%BA。
〈線上影片廣告：觀看情境對廣告的影響〉（2017）。《Ipsos》。取自https://www.ipsos.com/sites/default/files/ct/publication/documents/2017-10/P065_CNT_YouTube-Video-Ad-Viewability.pdf。
謝宗霖、羅新興（2009）。〈網頁訊息對瀏覽者回憶與消費意願的影響-以探討涉入的干擾效果〉。《中華管理評論國際學報》，12（4）。取自http://cmr.ba.ouhk.edu.hk/cmr/webjournal/v12n4/CMR251C09.pdf。
英文部分
Alhabash, S., & Ma, M. (2017). A tale of four platforms: Motivations and uses of Facebook, Twitter, Instagram, and Snapchat among college students?. Social Media+Society,3(1),2056305117691544. https://doi.org/10.1177/2056305117691544
Barclays (2018). Gen Z: Step aside Millennials. Retrieved from https://www.investmentbank.barclays.com/our-insights/generation-z.html
Coelho, R., Oliveira, D., & Almeida, M. (2016). Does social media matter for post typology? Impact of post content on Facebook and Instagram metrics. Online Information Review, 40, 458–471. https://doi.org/10.1108/OIR-06-2015-0176
Chiang, H., & Hsiao, K. (2015). YouTube stickiness: the needs, personal, and environmental perspective. Internet Research, 25, 85–106. https://doi.org/10.1108/IntR-11-2013-0236
Cheung, T. T. (2014). A study on motives, usage, self-presentation and number of followers on Instagram [Master’s thesis]. Retrieved from http://lbms03.cityu.edu.hk/oaps/ss2014-4595-ctt656.pdf
Court, D., Elzinga, D., Mulder, S., & Vetvik, O. (2009). The consumer decision journey. The McKinsey Quarterly, (3). Retrieved from http://search.proquest.com/docview/224538362/
DeVellis, R. F. (2012). Chapter 6: Factor Analysis. Scale development: Theory and applications, 26.
Duncan (2002): Evaluating the IMC processes (pp. 726-732).
Dimmick, J., Chen, Y., & Li, Z. (2004). Competition Between the Internet and Traditional News Media: The Gratification-Opportunities Niche Dimension. Journal of Media Economics, 17, 19–33. https://doi.org/10.1207/s15327736me1701_2
Edelman, D. C. (2010). Branding in the Digital Age. Harvard Business Review, 88, 14-18. Palgrave Macmillan. doi:10.1108/eb040166
Dimmick, J., Kline, S., & Stafford, L. (2000). The Gratification Niches of Personal E-mail and the Telephone: Competition, Displacement, and Complementarity. Communication Research, 27, 227–248. https://doi.org/10.1177/009365000027002005
Dimmick, J. (1993). Ecology, economics, and gratification utilities, media economics:Theory and practice, 135-156. Hillsdale, NJ: Lawrence Erlbaum Associates, Inc.
THE TRENDS TO KNOW FOR 2019 (2019). GlobalWebIndex. Retrieved from https://www.globalwebindex.com/2019-consumer-trends.
Gao, Q., & Feng, C. (2016). Branding with social media: User gratifications, usage patterns, and brand message content strategies. Computers in Human Behavior, 63, 868–890. https://doi.org/10.1016/j.chb.2016.06.022
Godey, B., Manthiou, A., Pederzoli, D., Rokka, J., Aiello, G., Donvito, R., & Singh, R. (2016). Social media marketing efforts of luxury brands: Influence on brand equity and consumer behavior. Journal of business research, 69, 5833-5841. https://doi.org/10.1016/j.jbusres.2016.04.181
Gu, B., & Ye, Q. (2014). First step in social media: Measuring the influence of online management responses on customer satisfaction. Production and Operations Management, 23, 570-582. https://doi.org/10.1111/poms.12043
Gatautis, R., & Kazakevičiūtė, A. (2012). Consumer behavior in online social networks: review and future research directions. Economics and management, 17, 1457-1463. https://doi.org/10.5755/j01.em.17.4.3014
Gülnar, B., Balcı, Ş., & Çakır, V. (2010). Motivations of Facebook, You Tube and similar web sites users. Bilig, 54(Summer 2010), 161-184. Retrieved from http://bilig.yesevi.edu.tr/yonetim/icerik/makaleler/2656-published.pdf
Gulati, R., & Oldroyd, J. B. (2005). The quest for customer focus. Harvard Business Review, 83, 92-101.
Huang, Y. T., & Su, S. F. (2018). Motives for instagram use and topics of interest among young adults. Future Internet, 10, 77. https://doi.org/10.3390/fi10080077
Haridakis, P., & Hanson, G. (2009). Social interaction and co-viewing with YouTube: Blending mass communication reception and social connection. Journal of Broadcasting & Electronic Media, 53, 317-335. https://doi.org/10.1080/08838150902908270
IBM (2017). Uniquely Generation Z. Retrieved from https://www.generationy20.com/retail-generation-z.PDF
Klobas, J. E., McGill, T. J., Moghavvemi, S., & Paramanathan, T. (2019). Problematic and extensive YouTube use: first hand reports. Online Information Review, 43, 265-282. https://doi.org/10.1108/OIR-01-2018-0032
Klobas, J. E., McGill, T. J., Moghavvemi, S., & Paramanathan, T. (2018). Compulsive YouTube usage: A comparison of use motivation and personality effects. Computers in Human Behavior, 87, 129-139. https://doi.org/10.1016/j.chb.2018.05.038
Khan, M. L. (2017). Social media engagement: What motivates user participation and consumption on YouTube?. Computers in Human Behavior, 66, 236-247. https://doi.org/10.1016/j.chb.2016.09.024
Koroleva, K., & Kane, G. (2017). Relational affordances of information processing on Facebook. Information & Management, 54, 560–572. https://doi.org/10.1016/j.im.2016.11.007
Kim, J., Kim, S., & Nam, C. (2016). Competitive dynamics in the Korean video platform market: Traditional pay TV platforms vs. OTT platforms. Telematics and Informatics, 33, 711–721. https://doi.org/10.1016/j.tele.2015.06.014
Keller, K. L. (2016). Unlocking the power of integrated marketing communications: how integrated is your IMC program?. Journal of Advertising, 45, 286-301. https://doi.org/10.1080/00913367.2016.1204967
Kim, J., Kim, S., & Nam, C. (2016). Competitive dynamics in the Korean video platform market: Traditional pay TV platforms vs. OTT platforms. Telematics and Informatics, 33, 711–721. https://doi.org/10.1016/j.tele.2015.06.014
Krause, A. E., North, A. C., & Heritage, B. (2014). The Uses and Gratifications of using Facebook music listening applications. Computers in Human Behavior, 39, 71e77. https://doi.org/10.1016/j.chb.2014.07.001
Ko, H., Cho, C. H., & Roberts, M. S. (2005). Internet uses and gratifications: A structural equation model of interactive advertising. Journal of advertising, 34, 57-70. Retrieved from http://search.proquest.com/docview/236570329/
Kaye, B., & Johnson, T. (2004). A Web for all reasons: uses and gratifications of Internet components for political information. Telematics and Informatics, 21, 197–223. https://doi.org/10.1016/S0736-5853(03)00037-6
Kaiser, H. F. (1974). An index of factorial simplicity. Psychometrika, 39, 31-36.
Kaiser, H. F. (1958). The varimax criterion for analytic rotation in factor analysis. Psychometrika, 23, 187-200.
Larsson, A. O. (2018). The news user on social media: A comparative study of interacting with media organizations on Facebook and Instagram. Journalism studies, 19, 2225-2242. https://doi.org/10.1080/1461670X.2017.1332957
Lu, W., & Hampton, K. (2017). Beyond the power of networks: Differentiating
network structure from social media affordances for perceived social support. New Media & Society, 19, 861–879. https://doi.org/10.1177/1461444815621514
Lemon, K. N., & Verhoef, P. C. (2016). Understanding customer experience throughout the customer journey. Journal of marketing, 80, 69-96. https://doi.org/10.1509/jm.15.0420
Lai, C. Y., & Yang, H. L. (2016). Determinants and consequences of Facebook feature use. New Media & Society, 18, 1310-1330. https://doi.org/10.1177/1461444814555959
Lee, E., Lee, J. A., Moon, J. H., & Sung, Y. (2015). Pictures speak louder than words: Motivations for using Instagram. Cyberpsychology, Behavior, and Social Networking, 18, 552-556. https://doi.org/10.1089/cyber.2015.0157
Malik, A., Dhir, A., & Nieminen, M. (2016). Uses and Gratifications of digital photo sharing on Facebook. Telematics and Informatics, 33(1), 129e138. https://doi.org/10.1016/j.tele.2015.06.009
Meyer, C., & Schwager, A. (2007). Understanding customer experience. Harvard business review, 85(2), 116. Retrieved from http://search.proquest.com/docview/70260209/
Mierzjewska, B. I., & Hollifield, C. A. (2006). Theoretical approaches in media management research. In Handbook of media management and economics (pp. 49-78). Routledge.
de Oliveira, R., Pentoney, C., & Pritchard-Berman, M. (2018). YouTube needs: understanding user’s motivations to watch videos on mobile devices.Proceedings of the 20th International Conference on Human-Computer Interaction with Mobile Devices and Services, 1–11. https://doi.org/10.1145/3229434.3229448
Prasad, S., Gupta, I., & Totala, N. (2017). Social media usage, electronic word of mouth and purchase-decision involvement. Asia-Pacific Journal of Business Administration, 9, 134–145. https://doi.org/10.1108/APJBA-06-2016-0063
Park, N., & Lee, S. (2014). College students' motivations for Facebook use and psychological outcomes. Journal of Broadcasting & Electronic Media, 58, 601-620. https://doi.org/10.1080/08838151.2014.966355
Pempek, T. A., Yermolayeva, Y. A., & Calvert, S. L. (2009). College students' social networking experiences on Facebook. Journal of applied developmental psychology, 30, 227-238. https://doi.org/10.1016/j.appdev.2008.12.010
Ritchie, J., Lewis, J., Nicholls, C. M., & Ormston, R. (Eds.). (2013). Qualitative research practice: A guide for social science students and researchers. sage.
Roy, S. K. (2009). Internet uses and gratifications: A survey in the Indian context. Computers in Human Behavior, 25, 878-886. https://doi.org/10.1016/j.chb.2009.03.002
Sheldon, P., & Newman, M. (2019). Instagram and American Teens: Understanding Motives for Its Use and Relationship to Excessive Reassurance-Seeking and Interpersonal Rejection. The Journal of Social Media in Society, 8, 1-16.
Shane-Simpson, C., Manago, A., Gaggi, N., & Gillespie-Lynch, K. (2018). Why do college students prefer Facebook, Twitter, or Instagram? Site affordances, tensions between privacy and self-expression, and implications for social capital. Computers in Human Behavior, 86, 276-288. Retrieved from http://search.proquest.com/docview/2093196713/
Sheldon, P., Rauschnabel, P. A., Antony, M. G., & Car, S. (2017). A cross-cultural comparison of Croatian and American social network sites: Exploring cultural differences in motives for Instagram use. Computers in Human Behavior, 75, 643-651. https://doi.org/10.1016/j.chb.2017.06.009
Sheldon, P., & Bryant, K. (2016). Instagram: Motives for its use and relationship to narcissism and contextual age. Computers in human Behavior, 58, 89-97. https://doi.org/10.1016/j.chb.2015.12.059
Stein, A., & Ramaseshan, B. (2016). Towards the identification of customer experience touch point elements. Journal of Retailing and Consumer Services, 30, 8-19. https://doi.org/10.1016/j.jretconser.2015.12.001
Sundar, S., & Limperos, A. (2013). Uses and Grats 2.0: New Gratifications for New Media. Journal of Broadcasting & Electronic Media, 57, 504–525. https://doi.org/10.1080/08838151.2013.845827
Smock, A. D., Ellison, N. B., Lampe, C., & Wohn, D. Y. (2011). Facebook as a toolkit: A uses and gratifications approach to unbundling feature use. Computers in Human Behavior, 27, 2322e2329. https://doi.org/10.1016/j.chb.2011.07.011
Shao, G. (2009). Understanding the appeal of user-generated media: a uses and gratification perspective. Internet research, 19, 7-25. https://doi.org/10.1108/10662240910927795
Varkaris, E., & Neuhofer, B. (2017). The influence of social media on the consumers’ hotel decision journey. Journal of Hospitality and Tourism Technology, 8, 101-118. https://doi.org/10.1108/JHTT-09-2016-0058
We Are Social & Hootsuite, Task Force. (2019). Digital 2019 Global Digital Overview (January 2019) v01. Retrieved from https://www.slideshare.net/DataReportal/digital-2019-global-digital-overview-january-2019-v01?from_action=save
We Are Social & Hootsuite, Task Force. (2018). Digital in 2018 Global Overview. Retrieved from https://www.slideshare.net/wearesocial/digital-in-2018-global-overview-86860338?ref=https://digitalreport.wearesocial.com/
Whiting, A., & Williams, D. (2013). Why people use social media: a uses and gratifications approach. Qualitative Market Research: An International Journal, 16, 362–369. https://doi.org/10.1108/QMR-06-2013-0041
Yi, K., & Sung, Y. (2007). What to read in the morning? A niche analysis of free daily papers and paid papers in Korea. The International Journal on Media Management, 9, 164-174. Retrieved from http://search.proquest.com/docview/220296974/
Zolkepli, I. A., & Kamarulzaman, Y. (2015). Social media adoption: The role of media needs and innovation characteristics. Computers in Human Behavior, 43, 189-209. https://doi.org/10.1016/j.chb.2014.10.050