There are various kinds of search tools on the Internet. This includes directories, search engines, and search services such as metasearch engines. Although the Internet is now one of the first places we go when finding information, it is important to consider all the resources available including books, journals, and other offline materials. The search process can be most successful when we consider all available resources and their appropriate uses. Even once you have decided to use the Internet to find information, it is important to decide what search tool to use, or where to look.

The "Invisible" Web

Most search tools only provide a snapshot of what's available online. There are thousands if not millions of resources on the Internet that many do not have access to. This is considered the "Deep," "Invisible," or "Hidden" Web. According to the Online Computer Library Center (OCLC), there are over 8,700,000 Web Sites on the Internet. This does not include the number of Web pages or documents included in each of the Web sites. That is actually a small number compared to how many resources are really online. For more interesting Web statistics, visit the OCLC. To learn more about the "Invisible" Web, try the Bare Bones 101 tutorial, Gateways and Subject-Specific Databases, by Beaufort Library at the University of South Carolina. The "Invisible" Web therefore:

• often points to specialized or expert sources
• comprises the majority of the material on the Internet
• is publicly accessible through many topic specific databases
• provides better quality content than the "Visible" or "Surface" Web

Search Engines

Search engines use indexing spider software that crawls from hyperlink to hyperlink indexing a Web page's content. The spider often crawls the Web on a scheduled basis. Search engines then list the indexed version of the Web at the time the spider last crawled the pages. Search engines therefore:

• provide computer (spider) selected information
• are searchable by keyword with operators such as plus (+), minus (-), double quotation marks (" ")
• are updated or crawled on a scheduled basis, for example monthly
• provide access to a wide range of resources
• are useful for searching for static information
• traditionally favor commercial sites

Beaufort Library at the University of South Carolina again provides detailed information on the definition of a search engine and metasearch engine. Explore the tutorial, Search Engines, to learn more about what a search engine is and how it works.

Directories

Directories use real people (not computers) to populate their collections. A directory's staff reviews and classifies links into topic or subject categories. Directories therefore:

• provide human reviewed and selected information for higher quality of content
• are organized by subject or topic similar to a library
• require more frequent maintenance on Web pages that have moved or no longer work
• are useful for searching for dynamic information such as weather, stocks, or news
• provide fewer results than search engines
• are useful for general information searches and browsing

Explore the Bare Bones 101 tutorial, Subject Directories, to learn more about what a directory is and how it works. Some search tools are now offering both a search engine as well as a directory. Google and AltaVista now offer both tools as well as several other search features. Finally, Bare Bones offers a closer look at a few search tools. Most people get to know one search tool and use it exclusively. Take some time to explore and try out each of the specific search tools. You may find a couple that you like.