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Search engine classification: in Guangzhou yongle air-conditioning repair Network, began to contact with SEO-related technology, I find out the knowledge to share with you, hehe, hope for everyone useful. The search engine according to its working method can divide into three kinds mainly, is the Full-text search engine (full text searches Engine), Catalog index class search engine (search index/directory) and meta search engine (meta search Engine).
Full-text Search Engine
Full-Text search engine is a veritable search engine, foreign representative has Google, Fast/alltheweb, AltaVista, Inktomi, Teoma, WISEnut, etc., the famous domestic Baidu. They are based on the information extracted from the Internet (mainly on the Web page text), the database to retrieve the relevant records matching the user query criteria, and then in a certain order to return the results to the user, so they are the real search engine.
from the perspective of the source of the search results, full-text search engine can be subdivided into two kinds, one is to have their own search program (Indexer), commonly known as "Spider" (Spider) program or "Robot" (Robot) program, and build a Web database, search results directly from their own database, For example, the 7 engines mentioned above, the other is the database that rents other engines, and arranges search results in a custom format, such as the Lycos engine.
Directory Index
Directory Index Although has the search function, but in the strict sense is not the real search engine, is only the Directory Classification website link list. Users can simply not use the keyword (Keywords) query, rely on the category directory can also find the information needed. The most representative of the directory index is the famous Yahoo Yahoo. Other notable are open Directory Project (DMOZ), LookSmart, about, and so on. Domestic Sohu, Sina, NetEase search also belong to this category.
Meta search (meta search Engine)
The
meta search engine, while accepting a user query request, searches on several other engines and returns the results to the user. The famous meta search engine has InfoSpace, dogpile, Vivisimo, etc. (Meta search engine list), Chinese search engine has a representative search engine. In the order of search results, some directly arrange search results by Source engine, such as dogpile, while others rearrange the results according to custom rules, such as Vivisimo.
In addition to the above three types of engines, there are several non-mainstream forms:
1, a collection of search engines: such as HotBot in the end of 2002 launched the engine. The engine is similar to a meta search engine, but the difference is that instead of calling multiple engines to search at the same time, the user chooses from among the 4 engines provided, so it's more accurate to call it a "collection" search engine.
2, the portal search engine: such as AOL search, MSN Search, and so on, although provide a searching service, but their own that is not categorized directory and no Web page database, its search results entirely from other engines.
3, Free link list (for all links, referred to as FFA): This kind of web site generally only simply scroll to arrange link entries, a small number of simple categories, but the scale is much smaller than the Yahoo directory index.
as the above Web site provides users with search query services, for convenience, we usually refer to it collectively as a search engine.
