When you comment on a blog post, you are usually allowed to include a link back to your website. This is often abused by spammers and can become a negative link building tool. But if you post genuine comments on high-quality blog posts, there can be some value in sharing links, as it can drive traffic to your site and increase the visibility of your brand.
A backlink is a reference comparable to a citation. The quantity, quality, and relevance of backlinks for a web page are among the factors that search engines like Google evaluate in order to estimate how important the page is. PageRank calculates the score for each web page based on how all the web pages are connected among themselves, and is one of the variables that Google Search uses to determine how high a web page should go in search results. This weighting of backlinks is analogous to citation analysis of books, scholarly papers, and academic journals. A Topical PageRank has been researched and implemented as well, which gives more weight to backlinks coming from the page of a same topic as a target page.