大數據應用技術對資訊經濟、科學發展與商業利益帶來極大貢獻，然而資訊主體經常於不知情下被他人蒐集其各種資料，滋生隱私侵害疑慮，不過隱私保護須與社會其他價值進行權衡，或可透過去識別化作法，以確保資料處理合法性。法律雖對個資有其定義，但是否所有與個人有關之資訊皆屬值得保護之個資，有其疑問。本文透過檢討2014年一則司法判決，探討行動電話用戶之所屬電信業者別是否屬於法律所保護之個資，結論提出不可合理期待之隱私資訊，或經適度去識別化後可供利用之資訊，應可運用於大數據時代資料的探勘與分析，以創造資料經濟之效率，並有利於公共利益與福祉之最大化。

The technologies of big data applications can help private and public sectors analyze predictive information and thus to develop new services. However, the data subjects are often unware of their personal data collected by others and generates the concerns of privacy invasion. We should weigh the value of the privacy protection among other societal values. The data protection law defines the personal data; however, it is controversial whether all the information related to specific individual deserves the legal protection. This paper attempts to analyze a court case in 2014 to discuss whether the name of mobile carrier belongs to the personal data of such a subscriber. It concludes that the unreasonable expectation of privacy information or the appropriately de-identified information that is available for public use can make use of data mining and analytics in the era of big data and thus create the efficiency of the data economy and is beneficial to the public interest.