search engine does not really search the Internet, it is actually the search for a good web page index database.
the true meaning of the search engine, usually refers to the Internet to collect tens of millions to billions of web pages and for each word in the web page (i.e. keyword index), full-text database indexing search engine. When a user searches for a keyword, all pages that contain the keyword in the page content will be searched as a result of the search. After sorting through the complex algorithm, the results will be in accordance with the relevance of search keywords, ranking.
now the search engine has been widely used in the hyperlink analysis, in addition to the analysis of the index page content itself, but also to analyze the index of all the links pointing to a web page of the URL, AnchorText, or even around the link text. So, sometimes, even a "A does not have a word such as" Satan ", but if there is another" B link "Satan" to the "A", then the user can find web search A devil ". Also, if there are more pages (C, D, E, F…) Use the link to "A", or "F", or the source page of this link (B, C, D, E,…) The better, then the page A in the user search devil Satan will also be considered more relevant, ranking will be more forward.
The principle of
search engine, can be seen as the three step: grab the web page from the internet.
from the Internet capture program Spider system can automatically collect the "
in the index database search ranking
when users enter search keywords, the search system program page from the index database to find the key words of "comply with all relevant. Because all relevant web pages for the relevance of the keyword has long been good, so just in accordance with the relevance of the value of the sort, the higher the degree of relevance, the more forward.