A search services may find a website by accident, but odds are a website won't be indexed until formally registered. Upon registration of a website, the spider program will automatically visit the site and index the web page contents. Web surfers will then find the site via keyword searches. Examples of search engines are AltaVista, Excite, Lycos, InfoSeek, HotBot, WebCrawler, AOL NetFind and OpenText. Directories, the second type of search service, do not use spiders, rather they rely on the information submitted during registration.
Directories typically place a website into one or more predefined categories.
This allows people to conveniently find the website by navigating down a hierarchy of topics. Keyword search is also available in most directories. Because most surfers are busy or impatient, they typically only look at the first 30 or less website addresses returned from any particular search. Since most search engines limit the number of website addresses displayed to 10 per page, most people typically only look at the first three pages of results. With millions of web pages competing for front page honors, a well planned and executed search engine promotion strategy is required to achieve the desired top listing.