Like search engines, directories can be searched using online forms. In addition, users can browse the directory database based on lists of categories. The best known online Web directory is probably Yahoo , another is Looksmart . It is increasingly difficult to make any real distinction between search engines and online directories. Some writers on the Web class certain search engines as online directories, and vice versa.
Many beginners find online directories easier to use than search engines.
To get the best out of most search engines it is necessary to understand Boolean operators and to experiment with different keywords. You can search an online directory simply by clicking through lists of different subject headings and subheadings until you find the right topic. This convenience, however, comes at the cost of missing many potentially useful sites, as online directories tend to index a far smaller part of the Web than a big search engine such as Google. Meta-search engines are a very powerful tool for Web research. They allow you to submit a query to a number of different search engines at the same time.