Search Engine


A search engine is a computer program used to search for data. The search results are displayed as clickable links in the Search Engine Result Pages (SERP), which can be used to get the desired information.

In order to determine the relevance of a query to the existing data in the index, search engines today, work with sophisticated algorithms.

How it works[edit]

The work of a search engine is comparable to that of a librarian. However, unlike a library, a search engine saves items from websites, but usually only provides a hyperlink to the content you are looking for and not the content itself.

Before a search engine can display results, it first creates an index. There, all the data on websites are stored, such as the age or the number of links.

Data collection using the bot[edit]

The data for the search engine index is collected by a bot. This is a separate script or a program that automatically scans the web for content and stores the data found on a server. The bot follows hyperlinks on the websites it visits.

Data segmentation and categorization[edit]

All data relevant to a website are then categorized and segmented. When a user enters a search query, the search engine uses algorithms to determine which elements in their index are most relevant to this search. The algorithms used form the ranking criteria for placing the websites in the search results.

Areas of application[edit]

A search engine can be used for various purposes. In the scientific field, search engines are used in research. In the private sector, users often search for current information about events or products that they want to buy online. Search engines can also serve other purposes. These include navigation or searching for images and other media.

Alternatives to Google search[edit]

Whereas Google is currently the leading search engine provider in the world, there are other providers who distinguish themselves as an alternative to the Google search. Some of them have features that Google does not offer or they are particularly popular because of their strict privacy regulations.

  • Bing: The search engine of the Microsoft group offers similar search results as Google and has a similar appearance, but offers some additional interesting features includes playing videos in the thumbnail preview of the video search. This allows users to see what is shown in the video before actually clicking. In addition, the translation program BingTranslate can be started directly in another tab on bing.com. A separate search box can be used to get information on the current weather. Another advantage of Bing is that similar searches are placed prominently next to the input field.


  • Yahoo: Yahoo’s search engine reverts to the same index as Bing. This is similar to the search results. The homepage, unlike Google and Bing, has the character of a news portal. One special feature of the search engine is the special search for stars.


  • DuckDuckGo: The Internet search engine DuckDuckGo promises not to store user data or IP addresses. If you are seeking even more data security, you can do your search with DuckDuckGo using the Tor network. The search engine will sort the search results into categories for ambiguous terms which comes in handy. Moreover, DuckDuckGo provides links to appropriate recipes when entering food. Another special feature is that answers are provided to user questions. All features of the OpenSource project are further developed by a broad programmer community, which constantly improves the search results of DuckDuckGo.

Search engines for images[edit]

In addition to high relevancy to the search query, image search engines are characterized by the fact that the search results can be precisely filtered. At the same time, the sources are displayed for the displayed images. Typically, every image search has a child protection filter.

  • Google Images Search: With more than 10 billion images, Google’s Image Search is one of the largest data collections for web-based images. Through numerous filter options the search result can be exactly defined. In addition, Google offers the option to search images through an upload function. You can either upload a picture from your computer for this purpose or upload the link to the appropriate image source. Additionally, you can enter information about the image content in the search bar. That way, Google Image Search is a great tool to check if image content is illegally used on other websites.


  • Bing Image Search: The Bing image search engine is characterized by its good usability. After entering the search term, you get a clear view of the image sources. If you hover your mouse over an image, you get more information such as image size and image source. The display of related search results and the filter function can help narrow down the search results. To protect young users, the filter for offensive content is set to “strict.”


  • Yahoo Image Search: If you want to access the large image resources of the Flickr service as part of your image search then this search engine would be most suitable. In addition to images from professional photographers, you can also discover snapshots from private users. Alternatively, the search function on Flickr itself can be utilized.

Search engines for students[edit]

Scientifically oriented search engines or search engines for students often differ from the usual web search by the fact that the results refer to papers, dissertations or other publications. Important for university research are the catalogs of the university libraries called OPAC.

  • Metager: The meta search engine of the University of Hannover data center offers many different configuration options to refine search results. For example, entries from Wikipedia can be favored. This search engine is well equipped for a precise search, since Metager provides more results in addition to Google’s usual search engines.


  • Base: With this search engine organized by the University of Bielefeld, the web can be searched for scientifically relevant articles. The advantage of this is that both libraries and digital attachments are displayed. If you save your search as an RSS feed, you will always receive the latest search results for your search query when you call up the feed.


  • Encyclopedia Britannica: Encyclopedia Britannica can be searched. The index is limited to the contents of this encyclopedia.


  • Google Scholar: This search engine is recommended if you are looking for scientific essays, but also want to take a look at the book. In addition to scanned book pages, Google Scholar also provides information on the locations of the books and links to purchase opportunities. Google Scholar is highly recommended for writing scientific papers and researching secondary literature. Users logged into a valid Google account can also save search results and books.

Search engines for children[edit]

A search engine for children has the purpose of allowing children to search the web for age-appropriate content without content that could be harmful to young people.

  • fragFinn: Children can use the mascot Finn to search the web for content that is suitable for them. At the same time, the search engine provides additional features such as a URL check, which allows parents to check websites for their suitability for children. A red alarm button is prominently placed next to the search bar. Users can report sites that do not meet the criteria of the search engine.


  • BlindeKuh: This search engine provides only child-friendly search results from its own index. The age for which the content is appropriate is indicated with each search result. Moreover, the country from which the entry originates and the language in which it is available is also noted. The portal is also a very good starting point with thematically sorted surfing tips for children, recommendations for games, as well as a recipe collection.

Both these projects are not financing themselves through advertising like many other web search engines for children.

Search engines which no longer exist[edit]

At the end of the 1990s, the search engine market was even more diverse. However, many of the search engines that existed and were partially popular then, have either been discontinued or merged into other companies. These include: Altavista, Fireball, Inktomi, Infoseek, and Excite.