Hi Lesley,

I'm the head Data Scientist here at Moz and can answer some of your questions about the DA changes you've seen.  You are correct that tweeting a URL will eventually include it in our Mozscape index, nice detective work   The blog post announcing Just Discovered Links that Keri quoted (http://moz.com/blog/announcing-the-just-discovered-links-report) is a little outdated and we are now including these URLs in Mozscape.  This is a recent change that overall increases the freshness of the Mozscape data.

You are also correct that including more links to a site in the Mozscape index will generally improve DA and these links were missing before you tweeted them.  We know that the Mozscape index does miss some links, and are working hard to improve the coverage of all sites in our index.  However, we still believe that PA/DA are valuable as overall summaries of the importance for each page or domain.  For example, PA/DA are well correlated with Google search position (see:  http://moz.com/search-ranking-factors).