Web search engines use special software programs (called robots, spiders, or crawlers) to find Web pages and list (or index) all words within each one to make searching large quantities of pages faster. Indexes capture the largest amount of information on the Web, but no index lists everything on the Internet.
In addition to search engines, there are also:
- Specialized web search engines – A tool that has a specialty, usually either a subject or format focus. It ignores the rest of the information on the web. Examples include science.gov (http://www.science.gov/) and TinEye Reverse Image Search (https://www.tineye.com).
- Metasearch engines – Tools that search multiple web search engines and gives you results from all of them. Some of these return the best results from the search engines they search. Examples include Dogpile (http://www.dogpile.com) and WebCrawler (https://www.webcrawler.com).
- Web directories – Tools created by editors or trained researchers who categorize or classify web sites by subject. Directories are more selective than search engines. An example is the Directory of Open Access Journals (https://doaj.org/).
When to Use Them
Web Search Engines and related web search tools are helpful for locating background information, news (especially if it’s recent), and public opinion.
However, scholarly information is often not available through a regular web search. If you do find scholarly information through a web search engine, especially if you are off campus, you may be asked for payment to access it. Ohio State Libraries can usually get you what you need without additional payment.
Remember to follow the advice in Evaluating Sources to determine whether information you locate online is suitable for your information needs.
How to Use Them
See links above. Use of each tool varies. If a search engine has an advanced search, it may include options such as specifying format, language, domain, or date range.