In SEO (Search Engine Optimization), a “backlink” refers to a hyperlink from one website to another. Backlinks are crucial for SEO because they signal to search engines that other websites find the content on a particular site valuable and relevant. The logic is that if many high-quality sites link back to your content, search engines interpret this as a sign of the quality and relevance of your content, which can positively influence your site’s search engine rankings.

Backlinks can be seen as “votes” for a webpage, with the underlying assumption being that more votes (i.e., backlinks) from reputable sources increase a page’s credibility and authority in the eyes of search engines. However, not all backlinks are equally beneficial. The impact of a backlink on SEO depends on several factors, including:

  • The authority of the linking site: Links from high-authority, reputable sites are more valuable than those from low-quality, obscure sites.
  • Relevance: Links from sites that are closely related to your site’s topic or industry are more beneficial than links from unrelated sites.
  • The link’s attributes: Attributes such as “nofollow” can instruct search engines not to follow a link or pass on any authority from the linking site to the linked site. However, even nofollow links can have indirect SEO benefits by driving traffic and visibility.
  • Anchor text: The clickable text part of a hyperlink. Relevant and descriptive anchor text can provide search engines with additional context about the link’s target content, although excessive optimization of anchor text can be penalized.

Types by Qualities

4. Dofollow vs. Nofollow

  • Dofollow: By default, most links that are created are dofollow links, which pass on link equity (ranking power). These are the types of links that are beneficial for SEO.
  • Nofollow: Links with a rel=”nofollow” HTML tag applied to them tell search engines not to follow the link and that the link should not pass any link equity. Sites might use nofollow links to signal to search engines to ignore sponsored links or links generated through user-generated content like comments.

5. High Authority vs. Low Authority Links

  • High Authority Links: These come from reputable, well-established sites that have a high domain authority. Links from these sites are more valuable because they transfer more “authority” to your site.
  • Low Authority Links: Links from newer or less reputable websites have less impact on your SEO, although they can still contribute to your site’s link diversity and traffic.

6. Relevant vs. Irrelevant Links

  • Relevant Links: Links that come from websites related to your site’s industry or niche are more valuable because they signal to search engines that your content is relevant to your domain area.
  • Irrelevant Links: Backlinks from unrelated sites are less beneficial because they don’t contribute to the perceived relevance or authority of your website in a specific subject or industry.

Understanding these types of backlinks and how they affect SEO can help you craft a more effective link-building strategy, focusing on generating high-quality links that improve your site’s visibility and ranking on search engines.


Effective backlink strategies focus on earning high-quality, relevant links, which can improve a site’s SEO performance, increase its visibility in search engine results pages (SERPs), and drive organic traffic.