These operators can be very useful to help you structure a complicated search. A term that follows a plus sign must be included in the results retrieved and a term that follows a minus sign must not be included. There are many Internet searching tutorials available on the Web. Many of these include sections that compare the more popular search engines and describe their key features and search capabilities. What Directories Are and How They Work Directories, also known as subject guides and catalogues, are often a good starting point for researching a topic.
Directories are hierarchically organized lists of internet resources, generally manually compiled.
As these lists are generally created by people and based on some sort of subject classification, they tend to be smaller than the computer generated search engine keyword indexes. By pointing and clicking on the various headings in directories, you can move through the categories from general subjects to specific topics. Sites listed in these guides may have been submitted by their authors, or chosen by the editors of the directory for inclusion. The fact that sites have been reviewed before being included in a directory means that they have been selected on the basis of their relevance to a particular topic. Searching using directories tends to retrieve fewer results than searching using search engines, however the results tend to be of a higher standard.