Google focuses more on link quality than quantity of links for any particular website available on the world wide web.
Having tons of backlinks from multiple sources is not just the best strategy to improve your website rankings. More quantity does not mean better quality. Multiple spam backlinks can adversely affect your website. Getting backlinks from sources that have high spam scores can lead your website into trouble like a drop in search engine ranking and in severe cases, your website can get de-indexed from Google search.
Luckily there is a metric that can identify the spammy nature of a website known as Spam score. This score majorly useful for making better backlink decisions in SEO. In short, getting a lot of backlinks from a spammy (low credibility) website can harm your website than getting a good rank.
The spam-score concept was developed in 2015 by Dr. Matt Peters, Director of Moz. This indicates the spamminess level of a subdomain and how Google perceives it.
An important point to note here is spam score is mechanics operates at the sub-domain level. It means if you are getting a backlink from a sub-domain and having a very high spam-score that doesn’t mean its other pages or root page have the same spam score. (It could be high or low)
The spam score is high for those websites that have thin content i.e. not having reliable, quality, and in-depth content. Unless a website has subject matter expertise in a niche it is not considered a reliable source or worth backlinking. Even if a website is having a low number of internal links it may be marked as spam. Websites having good internal linking to their different pages help users to stay longer and provide an excellent experience.
A website must also maintain a good Do-follow & No-follow link ratio, website having higher do-follow links in comparison to no-follow depicts it is not earning links naturally.
Moz has classified spam scores and associated with a number of spam flags. If a website receives a number of flags between 1-4 then there is no or very low harm, but to maintain this you must get alert that it may not reach beyond 4. But if the number of spam flags is between 5 to 7 that means there is a medium level of risk to the website. The webmaster will also receive one warning to fix the spam issues.
But if the blog’s or website is getting more than 7 flags then there is a high level of spam risk. A website with a number of spam flags between 14 – 17 means, Google can blacklist the website and the website will never appear in Google’s search results.
Low quality and spammy backlinks are like cancer to your website. So before getting a backlink from any website you must first check the spam-score of that website.