The characteristics of search refer to how users search the Internet. Understanding how a search engine works helps you to understand how your pages are ranked in the search engine.
Broadly Search engines fall into three categories:: primary, secondary and targeted.
A primary search engine are most popular ones and which is the type that a surfer think of most often when search engines come to mind. This category of primary result driven services dominates the search market at present and is itself dominated by the ones you are most popular and commonest search engine names such as Google, Yahoo and MSN which covers. These search engines cover 70%, 20% and 10% market respectivly. Some index most or all sites on the Web. For example, Yahoo! Google, and MSN are primary or say major search engines. Each primary search engine differs slightly from the others. Search engines in this category use Spiders which are automated programs that browse and index webpages in a methodical manner, following links from one website to another. Spiders return the searched data to the search engine companies and which is used to provide the excerpts that you see in your proper search results as well as it forms a part of the search algorithm that they use to decide and display which search results are ranked highest. The Spiders also provide the search engine cached versions of web pages that you are able to see. On searching over search engine, we receive different results on each one as this difference in those search results is all in the algorithm that is used to create the search engine.
Secondary search engines are more audience specific ones. They don’t generate as much traffic as the primary search engines, but they’re useful for geographical or regional and more specifically focused searches. Examples of secondary search engines you’ll see that sites like AltaVista, AllTheWeb, Lycos, AOL and Netscape receive the majority of their search data directly from either Yahoo or Google. Secondary search engines, just like the primary ones, will vary in the way they rank search results. Some will rely more heavily upon keywords, whereas others will rely on reciprocal links. Still others might rely on criteria such as meta tags or some proprietary criteria. There are many other search engines like this out there that are trying to carve a niche by presenting the same search results in different ways.
Targeted search engines Search engines are very narrowly focused, usually to a general topic, like medicine or branches of science, travel, sports, or some other topic. Examples of targeted search engines include CitySearch, Yahoo! Travel, and MusicSearch, and like other types of search engines, ranking criteria will vary from one to another.