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In other words, I know Authorship is important & useful, but wrong at this point to say it is a direct factor in rankings
Nope, that's just the method of letting them know the author of an article, combined with a link back to the site from the G+ profile.
AuthorRank (a term that Google doesn't use) ....
@marktraphagen to be fair, it (i.e. author rank as stated in the question MC was answering) does come into play in some ways. For example, in-depth articles use that data, I'm pretty sure.
I'm sure it's coming, though in many cases I assume that the question of who wrote an article would be important (or desirable) only in personalized search.
If Author Rank or Authorship were to play a part in rankings, Google would have to have some sort of mechanism in place for the author to ratify the authenticity of an article/