For Search engines, links are considered as votes for popularity and importance in the existing autonomous opinion poll of the web. Using refined link analysis, the engines can discover how pages are connected to each other and in which specific ways. Links aren't the only thing in SEO, but search professionals assign a large portion of the engines' algorithms to link-related factors. The links are a medium through which engines can not only analyze the popularity of the websites and pages but can also metrics like trust, spam, and authority. Trustworthy websites mostly link to other trusted sites, while spammy sites receive very few links from trusted sources. In short, Links building of your website builds its reputation and popularity among the search engines.