Most directories use both the hierarchical and keyword search methods interactively.
While performing a hierarchical search, following topics from the general to the specific, most directories offer a search engine option. The further down the directory the keyword search is made, the narrower is the search field, and the fewer and more relevant the hits. It is easy to use. Also, information placed in a directory's database is reviewed and indexed first by skilled persons to ensure its value. Because the review and indexing process used by directories is so time consuming, the number of Web sites reviewed and indexed are limited.