tedster - 1:49 am on May 19, 2013 (gmt 0)
So, what's the evidence for a 'paid to pass page rank' update?
An excellent question. There is some scant evidence of that intention from February 23, but not for determining whether it's an algorithmic update or a new manual penalty action. Given that the timing followed closely on the penalty that Google handed out to Interflora my inclination is to think of this as a manual penalty and not an algorithm update
See Google's blog arcticle, A Reminder-About Selling Links [googlewebmastercentral.blogspot.com] from Feb 23
I also note that this current thread has not seen anyone joining in about such a drop for their sites on March 15. Our regular March Update thread does have a lot of buzz about SERP shifts on March 15 - so something did change - but there's nothing in that discussion about paid links at all. So let's be wary about building a new myth here without a solid established basis.