Simply 'surfing' the Web can be entertaining, but time consuming and eventually frustrating if you are really looking for specific stuff. Search engines are free to use .
Subject directories are like reference libraries.
Information is grouped under similar categories. Within these categories you focus in on the information you're after until you reach a page with the required information on it. The result of a directory search is a whole lot of matching categories which will lead to another list of matching categories and so on until you reach your final page. This process makes the use of directories a lot easier than other search engines. On the other hand, it requires quite a bit of browsing until you actually get to the right page.