Every day, a huge amount of new materials appears on the Internet: websites are created, old web pages are updated, photos and video files are uploaded. Without invisible search robots, it would be impossible to find any of these documents on the World Wide Web. There is currently no alternative to such robotic programs. What is a search robot, why is it needed and how do they function?
What is a search robot
A search robot for sites (search engines) is an automatic program that can visit millions of web pages, quickly surfing the Internet without operator intervention. Bots constantly scan the space of the World Wide Web, find new web pages and regularly visit already indexed ones. Other names for search robots: spiders, crawlers, bots.
Why search robots are needed
The main function that search robots perform is indexing web pages, as well as texts, images, audio and video files located on them. Bots check links, site mirrors (copies) and updates. Robots also monitor HTML code for compliance with the standards of the World Organization, which develops and implements technology standards for the World Wide Web.
What is indexing and why is it needed
Indexing is, in fact, the process of visiting a particular web page by search robots. The program scans texts posted on the site, images, videos, outgoing links, after which the page appears in the search results. In some cases, the site cannot be crawled automatically, then it can be manually added to the search engine by the webmaster. As a rule, this happens in the absence of external links to a specific (often only recently created) page.
How search robots work
Each search engine has its own bot, while the Google search robot can significantly differ in its mechanism of operation from a similar Yandex program or other systems.
In general terms, the principle of the robot’s operation is as follows: the program “comes” to the site via external links and, starting from the main page, “reads” the web resource (including viewing those service data that the user does not see). The bot can both move between the pages of one site, and go to others.
How does the program choose which site to index? Most often, the spider’s “journey” begins with news sites or large resources, directories and aggregators with a large link mass. The crawler continuously crawls pages one after another, the following factors affect the speed and sequence of indexing:
- internal : linking (internal links between pages of the same resource), site size, correct code, user friendliness, and so on;
- external : the total volume of the link mass that leads to the site.
First of all, a search robot searches for a robots.txt file on any site. Further indexation of the resource is carried out based on the information received from this particular document. The file contains exact instructions for the "spiders", which allows you to increase the chances of visiting the page by search robots, and therefore, achieve the site as soon as possible in the issuance of "Yandex" or Google.
Analog programs of search robots
Often, the term "search robot" is confused with intelligent, user or autonomous agents, "ants" or "worms." Significant differences exist only in comparison with agents, other definitions indicate similar types of robots.
So, agents can be:
- intellectual : programs that move from site to site, independently deciding what to do next; they are not common on the Internet;
- autonomous : such agents help the user in choosing a product, searching or filling out forms, these are the so-called filters that have little relation to network programs .;
- custom : programs facilitate user interaction with the World Wide Web; these are browsers (for example, Opera, IE, Google Chrome, Firefox), instant messengers (Viber, Telegram) or email programs (MS Outlook or Qualcomm).
"Ants" and "worms" are more like search spiders. The former form a network between themselves and interact seamlessly like a real ant colony, while “worms” are able to reproduce themselves, otherwise they act the same way as a standard search robot.
Varieties of Search Robots
There are many varieties of search robots. Depending on the purpose of the program, they are:
- "Mirror" - view duplicate sites.
- Mobile - target mobile versions of web pages.
- High-speed - they capture new information quickly, viewing the latest updates.
- Referential - index links, count their number.
- Indexers of various types of content - separate programs for text, audio and video, images.
- Spyware — Searches for pages that are not yet displayed in the search engine.
- "Woodpeckers" - periodically visit sites to check their relevance and performance.
- National - view web resources located on the domains of one country (for example, .ru, .kz or .ua).
- Global - index all national sites.
Major Search Engine Robots
There are also separate search engine robots. In theory, their functionality can vary significantly, but in practice the programs are almost identical. The main differences between web page indexing by robots of the two main search engines are as follows:
- Severity of verification. It is believed that the Yandex search robot mechanism evaluates the site for compliance with the World Wide Web standards somewhat more strictly.
- Preservation of the integrity of the site. The Google search robot indexes the entire site (including media content), Yandex can selectively browse pages.
- The speed of checking new pages. Google adds a new resource to the search results within a few days, in the case of Yandex, the process can take two weeks or more.
- The frequency of reindexing. The Yandex search robot checks for updates a couple of times a week, and Google - once every 14 days.
The Internet, of course, is not limited to two search engines. Other search engines have their own robots that follow their own indexing parameters. In addition, there are several "spiders" that are not developed by large search resources, but by individual teams or webmasters.
Common misconceptions
Contrary to popular belief, spiders do not process the information received. The program only scans and saves web pages, and completely different robots are engaged in further processing.
Also, many users believe that search robots have a negative impact and are "harmful" to the Internet. Indeed, individual versions of spiders can significantly overload the server. There is also a human factor - the webmaster who created the program can make mistakes in the robot settings. Nevertheless, most of the current programs are well designed and professionally managed, and any problems that arise are quickly resolved.
How to manage indexing
Search bots are automated programs, but the indexing process can be partially controlled by the webmaster. This greatly helps the external and internal optimization of the resource. In addition, you can manually add a new site to the search engine: large resources have special forms for registering web pages.