External links are, in fact, advertising a particular site on the Web and how the site is presented on other resources. In short, without such links it would be impossible to find sites on the Internet. The importance is obvious, which means that checking the site for external links is an important component of optimization and the current assessment of the technical condition of the resource, which is carried out by regular means without involving outside specialists. Existing search engine optimization tools offer different verification methods, but they are all based on search engine data. It is not difficult to check external links from the site, but some problems identified in this way can be difficult in the process of their localization.
All external links, as noted above, are registered by search engines and their full list can always be found on the administrative panels of all the major search engines. The presentation of data can be organized in different ways, but the work of search robots on all sites is exactly the same. Robots collect such links by simply clicking on links from other sites. Along the way, the information gathered with them is also of great statistical value, both for search engines and for the owner of the resource. Most likely, site owners do not see even half of the information that is collected by search robots for internal use of search engines. However, given that such information is provided completely free of charge, search engines can say thank you for that.
So, the most relevant and, perhaps, the main thing is the thematic focus of the content of sites that contain links to the site in question. This directly affects the "weight" and "credibility" of this link. Link weight is a conditional value that is directly related to the PR resource from which the link goes. The credibility of the link depends on how much the keyword associated with the link matches the thematic focus of the resource. If external links come from sites that have good PR (> 4), then several hundred or thousands of such links help increase the PR of the site on which they "work". Otherwise, the PR of the site referred to by the links remains unchanged.
If we talk about external links, like those that are posted on the site in question, it can be argued that they increase the "credibility" of the resource. This means that this site “knows” more about other resources that contain content of a certain semantics. In general, if we talk about the importance of external links for any Internet resource, then this significance lies, firstly, in the presence of
explicit connection with a certain segment of the Network, and, secondly, in the awareness of the resource itself about the existence of other sites similar in content. The latter factor is crucial for search engines because they rely on data grouped in this way.
In conclusion, we can add that the absence of "dead" links on the site indicates its "correctness" in relation to users and search engines; and the presence of links that do not lead anywhere or where they should lead leads to search fines. The latter have a very negative effect on the overall rating of a site on the Internet. That is why, site administrators and all optimizers are fighting for the full compliance of external links with the content and navigation of trust sites.