External links are, in fact, advertising of 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 the optimization and current assessment of the technical condition of the resource, which is carried out by regular means without involving specialists from outside. Existing search engine optimization tools offer different ways to check, but they are all based on search engine data. It's not difficult to check external links from a site, but some of the problems identified in this way can be difficult to localize.
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 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 simple clickslinks from other sites. Along the way, the information collected 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 the internal use of search engines. However, given that such information is provided completely free of charge, we can say "thank you" to the search engines for this.
So, the most relevant and, perhaps, the most important is the thematic focus of the content of sites that contain links to the site in question. This directly affects the "weight" and "authority" of this link. Link weight is a conditional value that is directly related to the PR of the resource from which the link comes. The authority of the link depends on how the keyword associated with this link corresponds to the thematic focus of the resource. If external links come from sites that have a good PR (>4), then several hundred or thousands of such links help to increase the PR of the site they "work" for. Otherwise, the PR of the linked site remains unchanged.
If we talk about external links, like those posted on the site in question, it can be argued that they increase the "authority" of the resource. This means that this site "knows" more about other resources that have content of a certain semantics. In general, if we talk about the importance of external links for any Internetresource, this significance lies, firstly, in the presence of
obvious connection with a certain segment of the Web, and, secondly, in the awareness of the resource itself about the existence of other sites similar in content. The last factor is extremely important for search engines as 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 don't lead anywhere or where they should lead leads to search pen alties. The latter extremely negatively affect the overall rating of the site on the Internet. That is why site administrators and all SEOs strive to ensure that external links are fully consistent with the content and navigation of their sites.
