Directories are useful reference on various concepts and topics. It contains information about the companies the products they offer in the market. Directories tend to display high quality sites that have been pre-screened by a human editor. Directories are also useful for the structure they give to the Internet. Editors check to make sure that a site is active, that a site contains unique content, which it is not under construction, and that visitors can actually find their way around it. A directory on the other hand nearly always contains regional categories that can be easily browsed. Details regarding different services in a specific area can be accessed through web.