Change in MozTrust of the Domain
This alert is based on the normalized (ten-point, logarithmically-scaled) MozTrust of the paid-level domain of the source URL (Moz Documentation). Changes in MozRank are generally associated with a shift in the link graph for a site with links closer/further from a trusted link source such as University, Government Website, and similar.
Increase in MozTrust of the Domain
An increase in MozTrust for your domain indicates you have received links that are closer to a trusted source. This could mean you received a link directly from a trusted site, like a University, or that you have received links that have links from more trusted sites. This is a good indicator that your site is more trustworthy, and will contribute to higher rankings.
Decrease in MozTrust of the Domain
If the MozTrust for your domain is decreasing, that typically indicates you are losing links from trusted sources, or that links you have received are from sites that are losing links from Trusted sources. If you see this number dropping, you should check your backlink profile for any recently dropped links, and work to regain those links or replace them. Consistent drops in MozTrust can be an early indicator of lost rankings.
Let’s hope you have recently garnered new authoritative links to your site and you see this number on a steady upward trend. It is important to note that Moz can trigger false positives for this alert if there was a recent index update on their end, which would have an impact on the MozTrust of all sites in their index. If you see a big jump or drop, you should check to see if Moz updated their index before freaking out!