Finding information on the Internet has always been one of the most difficult things to do because of the amount of information and the diversity of tools used for delivery. But each time new information tools have been developed, people have created ways to search the information spaces these tools create. (See Net Spaces).
Keyword-oriented searching is like looking through the pages of a book or a dictionary to find information based on a word. This word could be a topic or term (e.g., photosynthesis) or a proper name (e.g., Ben Franklin, IBM, or Iowa). Typically, in a paper book, you would use the index to find out where in the book the word is mentioned.
Online search engines ask you for the keyword or words that you are looking for. The search engine then searches its database for Internet resources that contain your search word(s). The search tool makes entries in its database by periodically "crawling" the Web or Internet for information and recording the contents of Web pages.
Search tools that crawl the Web used to called spiders, but are now called search engines.
Today, there are Top Keyword searching tools available for you to use. These are primarily Web-based. A good resources to read is the Search Engine Tutorial by Pandia.
Some people prefer one search engine over another because of its features or because they've grown familiar with its use. For example, many people love the simplicity of Google's interface.
You can search the discussion forums of Usenet news articles using Google Groups. This gives you a fast way to search the deluge of discussions on Usenet for people discussing your keyword of interest.
All information isn't only on the publicly-accessible World Wide Web, however. You can use a directory such as CompletePlanet to find out about what has been called "the hidden Web" or "the deep Web"--specialized databases that may be Web-accessible, but are not examined by spiders or generally available to the general public without a fee.
In ancient times (before 1995), humans searched the Internet using tools such as "Gopher," "Archie," "Veronica," "WAIS," and others. Today, these tools are mostly obsolete, and the Web has become the dominant form of information dissemination and retrieval on the Internet.
You can learn more about modern and ancient Internet tools for information searching and exchange on the Internet.