Inbound External Links

Inbound external links (also called backlinks) direct from an external website to the website in question. An example of an inbound external link is an editorial mention on another website (for example, a news magazine may recommend the website in question and cite it as a source). Links from web directories, blogs, and forums are also regarded as inbound external links. Mentions on social networks like Facebook or Twitter are likewise included.

In contrast to inbound internal links, inbound external links are a ranking factor for Google and other search engines.


When the first search engines were developed for the Internet, a way to measure the quality of a website was sought after for quite some time. Backlinks or inbound external links were quickly identified as a possible source for measuring quality. Because such a hyperlink is theoretically a direct recommendation from one website to visit another in order to obtain even more information, or an offer to purchase there.

While initially the quantity of incoming links was the key factor, search engines are now working much more precisely and mainly analyze the quality of backlinks. It is believed that the following factors influence the quality of incoming external links:

  • Quality of the link-giving website
  • Anchor text
  • Type of the link-giving website: social media, info website, news site, etc.
  • Domain trust of the link-giving website
  • Number of outgoing links on the link-giving website
  • PageRank of the link-giving website
  • The link structure of the referring website
  • Class C network of the other site
  • IP address of the other website

Link building[edit]

Link building used to be a very simple SEO task for a long time, because quantity of backlinks was primarily being focused on. Today, after several radical Google updates, this task has become more complex as the search algorithms can quickly identify if a website contains an unnatural link profile. Generally, it could be assumed that simulated natural link growth is rather inconspicuous. But the more preferred approach is that good content will inevitably lead to voluntary linking. Massive link building through web directories or bookmarking services is now considered spam and is no longer practiced by reputable SEO agencies.

Relevance to search engine optimization[edit]

Inbound external links play an important role in SEO. The Google algorithm is based partially on the review of hyperlinks and their weighting. These KPIs are important indicators for a good ranking of a website. Not only the quantity, but especially the quality is of great importance. Google is continuing its efforts to improve its algorithm and to distinguish high quality inbound links from bad ones. Thus, naturalness, quality, and trust of backlinks are deciding factors today. You can identify good and bad inbound external links with an appropriate link checker.