Backlinks are those hyperlinks on a webpage which point towards the links of an external domain. In simple words it could be said that backlinks are used to make a connection between two websites. These are also called incoming links and inbound links.
Before the emergence of search engines, backlinks had no special purpose except for telling users about a website but now they play most important role in off page search engine optimization. Off page SEO refers to the techniques which a blogger use outside his webpages to improve the search engine rankings.
Popularity of a website is determined by the quality and quantity of backlinks in other websites. It helps in improving the Pagerank of a website that is directly related to more exposure in search results.
How Do Backlinks Help In SEO:Suppose you are a blog owner and performed an excellent on page SEO in your blog from all aspects and waiting for the traffic to come on your blog. You just wait for the traffic but receive no visitors to it so in the end you worry what is wrong with your blog? The answer is very simple, you haven't performed off-page SEO which consists mainly of backlink building. Search engines check for the number and quality of backlinks for a domain and then index the website associated with that domain in search engines according to it. This is the way how search engines perform indexing a website so it helps in receiving genuine traffic.
Backlinks Help In Improving Google Pagerank:Google pagerank is an algorithm by Google which tells the importance of a domain. It has values from 0 to 10. 0 is the least value and 10 is highest pagerank value which tells that the domain is highly popular. It is calculated by observing different factors among them most important is backlinks. The more quality backlinks a domain have, the more would be its pagerank.
Building backlinks on the websites which have higher pagerank value is good practice to improve pagerank because generally a quality backlink is considered as the backlink from high PR sites. A quality backlink is also measured by other criteria so it doesn't mean that you should avoid getting backlinks from sites with lower PR. You must build as many backlinks as you can from any source where you can get a backlink but remember not to spam or buy paid backlinks. It could result in your popularity falls. That's the real meaning of building quality backlinks.