In computer science a (also known as folder) directory is a grouping data file, a space on the computer where it is saved and stored information; icon that distinguishes him is the famous open with loose-leaf folder and that is all known. Instead on the Internet a web directory (also called positioning directory) is a database that contains the addresses of web pages, accompanied by the corresponding link, organized alphabetically, by category, or by topic for easier searching of the information usually happen that you resort to a directory in search of information and many confuse it with a search engine, but there is a real difference between the two. The difference between a search engine and a directory feature is that the latter does not possess search engines, robot or spider, but that they are handled by people. Directories will be constructing its databases according to searches not automated (with robots) and by warnings that include in them who raises a new page to the Web. Web addresses included in the directories are added by a person; When someone wants to register a web page should indicate the category where you want to include that page and have read and accepted the conditions of use. The contents of these are examined and processed by people visiting the newly added address to verify that they comply with a number of conditions and rules established and subject to the review of an editor who finally decided to grant, or not, the high. If you want your site to appear in a directory it is imperative that you register it manually, because but will not appear in the list.
The search results are usually displayed alphabetically and by categories. All directories have a very similar registration form to collect data and as your registration is manual many confuse it with a classified ads site. Most are free, but there are also those who require a payment or those who require an Exchange. It is important to repeat and underline that a directory is not a Finder, therefore not list web pages and not get results search by keyword, as it is done in a search engine; the information contained in a directory is organized by categories, subcategories, and so as I said before. I would say within the web directories best known are: Yahoo! and DMOZ. But the list of these sites not only is very broad, but varied, I think that it is better that you enter to Google and put the following routing directory listing you will see so many that you cannot imagine. Lots of luck!