Our Intro Post will be published very soon! But in essence, UA (UserAuthority) is a very complex computation of all accounts via (mostly) the Steem Follower Graph. Using that UA boils down to an "influence metric", for every account, and for every vote as well (we don't look at SP but the UA value of each voter, resulting in a combined score of an individual post).
Stay tuned! ;-)
OK, perhaps next time post on one of my more techy articles, as there is no relevance with this one. Which just makes me (and others) view it as spam.
Cg