Moz Page Authority is Moz’s calculated metric for how well a given webpage is likely to rank in Google’s search results (though obviously it is limited to overall authority and is not a keyword specific measure). It is based off data from the Mozscape web index and includes link counts, MozRank, MozTrust, and dozens of other factors.

As with Moz’s PageRank it is updated frequently which has made the Moz measures extremely useful, or at least interesting, with Google’s decision to stop sharing the updates to Google’s PageRank.