Moz Spam Score gives an idea of a site being banned/penalized by search engines. Spam score is for pages and sub domains only. It is not available for the root domains. Spam score is calculated based on the quantity of spam flags, a sub-domain triggers. Flags are created based on the potential factors that a site might be penalized by Google.

Spam score is very useful for checking the spammy links to a site. Getting a backlink from a spammy site makes our site vulnerable to penalty. So it is very important to check the spam score of a domain before getting a link from it.

Spam score cannot find every potentially bad link. It can guide us to find harmful sites. So we should manually check the sites and other parameters before taking any decision. Spam score is very useful while we are doing link cleaning or adding disavow files.

Spam score value ranges from 0 to 17. Spam score zero means the probability of spam is 0.5% while spam score 14 and above means the probability of spam is 100%. For a site with spam score zero to four, danger level is low. Spam score five to seven means the danger level is medium and spam score above seven means danger level is high.