[askalo]

Link building describes various methods that are used to generate links from other websites.
Search engines use links to crawl the web. In this way, Search Engines (e.g. Google) crawls both internal and external links of the web page. The aim of link building is to generate as many links as possible, which are classified by both users and search engines as high-quality and helpful.

so basically, it is very important for a good ranking on the search engine.