本文探討以問代查的網路問答服務系統之特性與發展，並以「台北市立圖書館線上參考服務」與「Yahoo!奇摩知識+」為對象，藉由問答內容分析、匿名實驗評鑑、與深度訪談，比較二者在系統功能、問答內容、及經營管理等面向之異同。研究結果顯示二者各有所長，但強調社群經營的網路問答服務模式，與圖書館界行之已久的參考諮詢服務模式的確有極大差異，值得發展數位或網路參考服務學習借鏡。最後本文也提出一些具體改善建議，提供參考。

This study aims to explore the characteristics and development of internet question-and-answer (Q&A) systems. Two representative systems in Taiwan, namely Taipei Public Library Online Reference Services (TPL) and Yahoo! Kimo Knowledge+ (Knowledge+), are investigated, using methods of Q&A content analysis, unobtrusive evaluation of reference services, and in-depth interview. The comparative analysis is threefold, including the aspects of system functions, Q&A content, and service model. The results respectively show the merits of the community-based model of Knowledge+ and the librarian-based model of TPL. However, many useful lessons can be learnt from Knowledge+ in the pursuit of enhanced digital or networked reference services of libraries. Suggestions on the improving of internet Q&A systems are also discussed in this paper.