Search engines are automated software systems that search the World Wide Web in a systematic way for information specified by a query. They then present results as a list, often called a search engine results page (SERP). The information may be textual or it might consist of images, video clips, infographics, articles and research papers. The process of searching and retrieving the information is called “indexing.”
A search engine uses automated software applications referred to as robots or spiders that travel along the links on the Web, collecting pages and content from various websites. They use this to build an index of pages and sites, and can store information between their visits, allowing rapid access when required.
When a query is entered, the search engine scans its indices to find matching pages and ranks them according to their relevance to the query. It then displays the relevant pages in order of ranking. The algorithms used by different search engines are not identical, and this is a significant reason why the same query will produce different results on the same search engine.
To help with the process of finding pages that meet the user’s requirements, several techniques can be used by the user. These include phrase searching, truncation and filtering. Phrase searching can be done by typing the search term into the search box with quotation marks around it, ensuring that the words are searched as a group rather than scattered throughout the site. If the word or words are too general, they can be truncated by placing them within double quotes, which will only return results that contain those exact words in the same order. Searches can also be made more targeted by including a filter in the search box, for example inurl: will search only the URL of the page, intext: will only search the body text of the page and intitle: will only look at page titles.
There are many different search engines online, and each of them can specialize in a particular type of information. Some examples are audio search engines for music files, video search engines, image search engines and e-commerce search engines. There are even search engines for searching through scholarly journals and library catalogs.
The processing load on a search engine can be enormous, since each query must be matched against the information stored in its indices. This can lead to the development of a number of complex techniques for adjusting a search engine’s behavior in order to improve the relevance of its results. These techniques are known as search engine optimization, or SEO. The result is a cat-and-mouse game between search engine specialists and website owners, who try to outwit the algorithm with ever-changing techniques. This can result in search engines changing their indices and rankings to reflect the latest trends. As a result, it’s important for users to stay abreast of the latest developments in search engine techniques. This will ensure that they can continue to get the most out of their favorite search engine.