Shaddows - 3:02 pm on Jan 14, 2013 (gmt 0)
Ref: potential new update
That Dec 21 update gave us a pretty hard slap. Lots of extra traffic, but a conversion rate about 1% (normally 1.7ish) and average order value down too.
Had another referral shift on 12/13th Jan, which seems to have reverted to previous ranking.
But, we monitor a lot of SERPs, and it doesn't look widespread. But then, the Dec21 update was pretty low key anyway.