General Remarks on Web Search

Web Directories

A web directory is a precompiler subject catalogue -- something like the subject catalogue in your local library - e.g. Arts, Science, Health, Business, News, Entertainment. If you're looking for information on the Web that fits neatly into an obvious subject or category, go first to a web directory. Yahoo is one of best known web directories. of these.

Search Engines

A web search engine is a program that enables you to seek out web pages containing specific words and phrases. With the search engine's help, you can locate individual appearances of such words in documents all over the Web.

Search engines use a number of different techniques including

• Keyword Search
• Concept Search

Initially, the two kinds of resource were sharply separated. Lately, better-known general purpose search sites usually include both components, though one may predominate.

Both kinds of resource require pages to be indexed. This is done in two ways:

1. Automatically by software programs known as "bots", spiders or crawlers. A robot is a piece of software that automatically follows hyperlinks from one document to the next around the Web. When a robot discovers a new site, it sends information back to its main site to be indexed.
2. On the basis of registered information that is has been supplied by users and web masters.