How search engines get the information they need to build their lists of results pages.
Search engines follow links. Links connect pages and documents to each other, much like roads connect villages and cities. By following these links, search engines collect data to show to their users. But how do they actually do it?
Search engines consist of three parts: the crawler, the index, and the algorithm. The process begins with a crawler that travels the web through links and pages. The crawler mainly looks for content-headings and site-structure.
The crawler goes around the internet 24/7, and when it passes through a website, it saves the HTML version of a page in an enormous database – called the index.
The index is updated every time the crawler comes around again and finds new information. In Google’s case, the crawler revisits your site more or less often depending on how often you change things, and how important Google thinks your site is.
How do vertical search engines prioritize the result pages and finally build their ranking?
Search engines use an algorithm for this. The algorithm takes the data from the index and calculates many factors that predict whether a result will be useful for the searcher.
Like we maintain our websites to say relevant, Google never stops re-evaluating their indexing database and algorithm. While we’re talking about links, both internal links (links from one part of your website to another part of your website) and external links (links from a different website to yours) have a tremendous effect on search engine rankings.
Site-speed, site-security, and quality of content are essential. But Google makes changes to the importance of all these different factors almost every day. Therefore, crawlers follow all the links on the web that they have access to continuously. This way, they can find new sites to index and change outdated information.
What ´s special with vertical search engines?
Vertical search engines use the same process but obviously follow a fundamental different objective. Like any generic search engine, vertical search engines consist of crawlers, an index, and an algorithm. But vertical search engines are trained to optimize in an extraordinary direction. You cannot find the same level of information in generic search engines like in vertical search engines.