It would appear that a number of people have received notifications from Google of unnatural link patterns similar to those received around late April. When the previous notifications were received a number of people were on the receiving end of devaluations of the link profiles and a subsequent loss of traction on their search results
Interestingly many people I have spoken to tonight suggest this is not on sites which we would expect to see such notifications on so whether this is a change of tack is still to be seen.
Further analysis of this is forthcoming but it would be interesting to see what the wider impact of this update is within the SEO community.
Updated: I should add the fact the emails are being sent out is not a direct sign that we can expect an update with Penguin. However the last time we had a spate of these notifications, the first of the Penguin updates followed shortly after. This may not be the same again this time round but one wouldn’t be surprised to see another update follow this within the short term future – whether that be an iteration of Penguin or Panda – or another new animal to the Zoo.