網際網路中的數位化資訊與傳統圖書館資源差異甚大，在邁入資訊網路社會的現在，為了掌握數位化資源的檢索與利用，圖書館有必要去了解其組織整理的方式。網路資源的使用方式可以透過檢索引擎或是主題指南，前者利用機器自動擷取，較容易且經濟。主題指南則經過一些人工加值工作，比前者費時費力費財。但此兩者均無法提供較詳細的資源描述給使用者，無法滿足使用者的資訊需求。要想有效率地進行資料檢索，metadata的建立是十分必要的。本文說明metadata之定義與功能、metadata的創作者與來源、metadata 的種類、metadata的架構與完整性等，最後說明圖書館界的回應。

　　　　　There exist lots of differences between information resources on the Internet and those in the traditional libraries. In order to retrieve and utilize digital information effectively in the coming era of information network, libraries have to explore how Internet resources are organized. Using search engines and subject gateway services are two common ways to retrieve and utilize Internet resources. Search engines are based on robot to extract metadata, which are automatic and are cheap to create. Subject gateway services add value through intellectual effort, and are correspondingly expensive. But neither approach is complete as users are interested in resources at various levels of granularity and aggregation which may not be satisfied by either of these two simplified approaches. In order to use the Internet resources effectively, the establishment of metadata is very important. This article describes the definitions and functions of metadata, a variety of metadata creators and sources, the different formats of metadata, the level of structure and fullness of metadata, and finally the responses and reactions from people in library field.