2.3网络( nternet)信息检索 Features Initial intention was more on resources sharing than iR Rapid development and constant improvement Wide usage Good for presenting information, less so for organizing formation IR capability Retrieval capability is an addition, not included in the original design for the system except in the case of WAis Quality(uneven retrieval performance) and quantity vary from one tool to another Replacing online systems and becoming the lab showcase for new advanced and sophisticated Ir techniques11 2.3 网络（Internet）信息检索 Features ¨ Initial intention was more on resources sharing than IR ¨ Rapid development and constant improvement ¨ Wide usage ¨ Good for presenting information, less so for organizing formation IR capability ¨ Retrieval capability is an addition, not included in the original design for the system except in the case of WAIS ¨ Quality (uneven retrieval performance) and quantity vary from one tool to another ¨ Replacing online systems and becoming the lab & showcase for new, advanced and sophisticated IR techniques