- Classification of types of Internet search engines
- 1- Hierarchical Seekers (Spider)
- To slide
- Indexed
- Calculate relevance
- Retrieve the result
- 2- Directories
- 3- Hybrid search engines
- 4- Metasearch engines
- References
The classification of internet search engines can be divided into hierarchical search engines, directories, hybrid search engines and meta search engines.
Search engines are a software system designed to find information on the World Wide Web. They use keywords to search for documents that relate to those words and then rank the results in order of relevance to the topic being searched.
Internet search engines seek to extract information that their user requires; this is possible due to a large database available on the internet.
They have become a tool for daily use to find information. Thanks to this, at present it is very easy to find information with search engines such as Google, AOL, Yahoo and Bing.
There are thousands of different search engines available on the Internet; each one has its different abilities and characteristics.
The first search engine developed was called Archie and it was used to search for FTP files; the first text-based search engine was called Veronica.
Users can access a search engine through the browser on a computer, smartphone, tablet, or any other electronic equipment.
Classification of types of Internet search engines
1- Hierarchical Seekers (Spider)
This type of search engine uses a 'spider' to search for websites on the Internet. This spider enters individual web pages, pulls out the keywords, and then adds the pages to the Internet search engine's database.
The advantages of this type of search engine is that they contain a large number of pages, and that they are easy to use. For this reason it is very common for the user to create a familiarity with it and to use it repeatedly.
On the other hand, the downsides include that because they extract so much data, it is quite possible to have too much information.
Most of the popular search engines on the Internet are hierarchical, such as Google, Bing, Yahoo, Baidu, and Yandex.
All hierarchical Internet search engines use a bot (spider) to find and index new content to the search database.
There are four basic steps that every hierarchical search engine follows before displaying any web page in search results:
To slide
Search engines crawl all over the Internet to find available web pages. This is done by a software called spider; the frequency between landslides can take days.
Indexed
It is the process of identifying the words and expressions that best describe the web page. The identified words are referred to as keywords and the page is assigned to the identified words.
Calculate relevance
The search engine compares the search string in the requirement string with the indexed pages of the database.
Because more than one page is more likely to contain the search string, the search engine begins to calculate the relevance of each of the pages in its index with the search string.
There are several algorithms for calculating relevance. Each of these algorithms has different relative weights for common factors such as keyword or link density.
That is why each of the search engines give different pages of results for the same search string.
From time to time search engines change their algorithms.
Retrieve the result
Basically it is simply displaying the results in the browser; the endless pages of search results that are ordered from most relevant to least important.
2- Directories
Directories are search engines that depend on human activities for their listings: a web page is submitted to the directory and its inclusion must be approved by the editorial team.
This process occurs as follows:
1-The owner of the website submits a short description of his site to the directory along with the category in which it should be listed.
2-The submitted site is manually reviewed. It can then be added to the appropriate category or it can be rejected from the listing. A site with good content is more likely to be added than a web page with poor content.
3-The keywords entered in the search box will be matched with the description of the web page. This means that changes made to the content of the site are not taken into consideration since only the description of the site matters.
The advantage is that each page is reviewed for relevance and content before being included. Often times having fewer results means that what you need can be found faster.
That being said, the format and layout is not friendly to most people and they may struggle with less common searches. Another disadvantage is that there is a delay in the creation of the web page and its inclusion in the directory
Some famous directories include the Open Dictionary Project, the Internet Public Library, and the recently closed DMOZ.
3- Hybrid search engines
These search engines use both hierarchical search engines and directories to list web pages in search results.
Most spider search engines, like Google, basically use hierarchical search engines as the primary mechanism and manual monitoring as the secondary mechanism.
Sometimes the user is given the option to search the web or a directory. At other times, a user may receive both human-curated results and hierarchical results in the same search; when this is the case, human results are usually listed first.
Google and Yahoo are two of the main search engines that fall into this category, although more and more search engines are migrating to this system.
4- Metasearch engines
These Internet search engines are those that search other search engines at the same time and then combine the results in a single list.
The advantage is that more results are obtained, but their relevance and quality can suffer considerably.
Examples of meta search engines include Dogpile, Metacrawler, and Clusty.
References
- What are different types of search engines (2016). Recovered from webnotes.com
- Searching the Internet: types of search engines. Recovered from libguides.astate.edu
- Types of search engines (2008). Recovered from zeald.com
- Search engines and its types (2015). Recovered from slideshare.com
- Search engine (2017). Recovered from computerhope.com