Hi Lesley,

The Mozscape index includes both pages that we crawl and pages that we discover links to from crawled pages but do not crawl.  We compute Page Authority for both sets of pages, but can only include links from pages we crawl.  In this case, these are pages that we discovered by crawling other pages but did not crawl them until you tweeted the URLs.

Regarding using traffic data in search ranking and PA/DA:  you are correct that we do not use Google Analytics data from one campaign in another campaign for the privacy reasons you mentioned.  I'd also be surprised if Google uses traffic data from Google Analytics directly in ranking.  In any case, since PA/DA are link authority metrics they only include link based metrics and do not use traffic or any of the other ranking signals (e.g. on page content, brand metrics, etc).  To analyze some of these other factors you can use our Keyword Difficulty tool (http://moz.com/researchtools/keyword-difficulty).  That said, while links are only a piece of the overall Google ranking algorithm they are still generally regarded to be the most important piece (e.g. see the survey and correlation results from our Ranking Factors study: http://moz.com/search-ranking-factors).

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Just Discovered Links that Keri quoted (http://moz.com/blog/announcing-the-just-discovered-links-report) is a little outdated and we are now including these URLs in Mozscape.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).