The links directed towards a website are called as back-links. Such inbound links are said to be the backbone of the website's development phase.
These links come up with more traffic along with good rankings. As the number of back-links to a website features the quality of a website, the owners of the website try to fetch as many back-links as possible.
But this cannot always help because there are some back-links that are not preferred by the search engine spiders. Special care must be taken while seeking for back-links from other websites.