Second, the hierarchical nature of subject directories can greatly reduce the odds of irrelevant information showing up in your search results. As the Internet has matured, subject directories have become more sophisticated and therefore even easier to search. These controls help speed searches by reducing the number of downloads needed to find a precise subject category. Infoseek's ActiveX page lets you make faster searches while reducing your number of page downloads. The hierarchical nature of subject directories reduces the number of irrelevant documents.
Subject directories are very enjoyable to browse.
Subject directories often contain a relatively small number of Web and Internet documents and tend to be Web-centric. Keyword indexes Keyword indexes are large databases that contain literally millions of documents and tens of billions of words. These indexes are so large that robot spiders and indexing computers must build, index, and maintain them. Table B. Let's look at an example of how a keyword index works. The index takes up more than 200 GB of disk space.