The external links directed to your website is Backlinks, which is the most prime aspect of SEO. The quality of backlinks can be determined by the authority of their website from where we get the backlinks.
A high volume of backlinks may be optimum but quality will be given higher authority than the volume of the backlinks. Search Engines uses sophisticated algorithms to identify and ignore the intentional links for ranking and penalize it. The at which the website gets the backlinks also monitored by the Search Engine if there is any aggressiveness in getting the backlinks then the website will be penalized.
the domain which is referring must also be reputed and should have the good authority and trust because if they are backlisted backlink will also affect your website.
Nofollow links should be utilized when you don’t want to pass or get the lime juice from the website. Paid links should be marked no follow, by saying this you are telling the spiders not to use these links to pass the values in both the positive and negative cases.
Website getting lot of backlinks for the relevant terms should have the anchor text which is varied naturally. Google’s Penguin algorithm targets on the links and find out overly optimized anchor text which is kind of black hat SEO will be resulting in penalties and loss of visibility for the website. Effectively optimized backlinks anchor text might incorporate brand name combined with keywords like “SEO Backlinks”.