TheOptimizationIdiot - 1:30 am on May 4, 2013 (gmt 0)
...so just switching the ecommerce to shop.example.com should be enough to bypass the flagged domain...
That makes me wonder.
Do you think it would be an idea to just stop the canonicalization of www and non-www, then let the one not "tagged" by penguin rank without redirecting? (IOW: Basically remove www non-www canonicalization, duplicate yourself and let Google decide to rank the version not impacted by Penguin.)