Links to sites are stored in a hierarchical directory structure .
Links are mostly to the front page of a web site.
Directory building is slow, time consuming work . Searches are typically only against the title and description of your site that are provided by you when you submit it or modified by the human reviewer in an effort to conform to the directories standards. When submitting your web site to a directory you are required to specify which sub-directory your site should be listed in . You typically must navigate through the web site it links to in order to find what you want. Composed of pages collected by servers called crawlers .