Because of the depth and breadth of information being indexed, there is usually a delay, sometimes up to several weeks, between the time a site has been“spidered”and when it appears in a search index.Until this two-step process has been completed, a site remains unavailable to search queries.
Finally, the heart of each search engine is an algorithm that matches keyword queries against the information in the index, ranking results in the order the algorithm deems most relevant.
Because the spiders, resulting indexes, and search algorithms of each search engine differ, so do the search results and rankings across the various search engines.This explains why a top 10 site in HotBot may not appear near the top of Alta Vista when the same keyword search criterion is entered.
In addition, many, but not all, search utilities also reference metatags—invisible HTML tags within documents that describe their content—as a way to control how content is indexed.As a result, proper use of metatags throughout a site can also boost search engine ranking.
因特網(wǎng)搜索工具分為兩大陣營：搜索引擎，如HotBot和AltaVista，以及在線目錄，如 Yahoo和Lycos。兩者間的差別與它們?nèi)绾尉幾W(wǎng)站編目有關(guān)。當然，對任何規(guī)律都有例外。有些搜索實用程序，如Ask Jeeves，把搜索引擎和目錄方法合并成單一的軟件包，希望把這兩個陣營中的東西提供給用戶。
在基于目錄的搜索服務(wù)中，Web網(wǎng)站編目是手工編撰的。比如一直流行的Yahoo就指定專門的人力資源來接受用戶對網(wǎng)站的建議，并對建議進行評價和分類，再把它們加到Y(jié)ahoo網(wǎng)站上特定目錄中。
Finally, the heart of each search engine is an algorithm that matches keyword queries against the information in the index, ranking results in the order the algorithm deems most relevant.
Because the spiders, resulting indexes, and search algorithms of each search engine differ, so do the search results and rankings across the various search engines.This explains why a top 10 site in HotBot may not appear near the top of Alta Vista when the same keyword search criterion is entered.
In addition, many, but not all, search utilities also reference metatags—invisible HTML tags within documents that describe their content—as a way to control how content is indexed.As a result, proper use of metatags throughout a site can also boost search engine ranking.
因特網(wǎng)搜索工具分為兩大陣營：搜索引擎，如HotBot和AltaVista，以及在線目錄，如 Yahoo和Lycos。兩者間的差別與它們?nèi)绾尉幾W(wǎng)站編目有關(guān)。當然，對任何規(guī)律都有例外。有些搜索實用程序，如Ask Jeeves，把搜索引擎和目錄方法合并成單一的軟件包，希望把這兩個陣營中的東西提供給用戶。
在基于目錄的搜索服務(wù)中，Web網(wǎng)站編目是手工編撰的。比如一直流行的Yahoo就指定專門的人力資源來接受用戶對網(wǎng)站的建議，并對建議進行評價和分類，再把它們加到Y(jié)ahoo網(wǎng)站上特定目錄中。