Planet13 - 5:12 pm on Aug 10, 2011 (gmt 0)
Before I would accept the whole user metrics theory as gospel, I would also look at how well the sites that are linking to me are doing.
Did those sites that have backlinks to your site suddenly regain their rankings, too? In that case, maybe the PR that is flowing from their site into your site is higher.
I say this because if user metrics played a significant role in ranking, then some of my highest ranking pages would have vanished from the SERPs long ago.