Glossary
What is Moz Spam Score?
Spam Score is Moz's estimate, from 1% to 100%, of the share of sites with similar features that Google has penalised or banned. It's based on signals Moz found common among penalised sites. A high Spam Score is a reason to look closer, not proof a site is spam.
How it's calculated
Moz studied sites that had been penalised or removed from Google and found features they often shared, such as thin content, few pages, unusual link patterns or missing contact information. Spam Score reports the percentage of sites with a similar set of features that were penalised. Moz groups scores as low (1% to 30%), medium (31% to 60%) and high (61% to 100%).
How to use it
As a filter. When vetting a list of directories, sort by Spam Score and manually check the high ones: does the site have real listings, traffic and review? Many small but legitimate sites get medium scores because they're small. A link farm usually fails on several other checks too.
What it isn't
It isn't a Google metric, and links from a high Spam Score site don't automatically hurt you. Google ignores most spammy links on its own. The concern is a pattern of links you built on such sites.
Example
A founder screens 120 directories from an old list. Fourteen have Spam Scores above 60%. Twelve of those turn out to be dead or link farms on inspection; two are small, real niche directories she keeps.
FAQ
Will a link from a high Spam Score site hurt me?
Usually not on its own. Google ignores most spammy links. Building many such links on purpose is the risk.
What is a good Spam Score?
Low (1% to 30%) is normal. Higher scores call for a manual look.
Can I see my own Spam Score?
Yes, in Moz Link Explorer.