It seems like Google is on a trend of telling webmasters which algorithms are impacting their site the most, at least in a negative way.
The other day a Googler told a webmaster that Panda was hurting their site, whereas now, Google's Matt Cutts is telling another webmaster that the Penguin algorithm is impacting their site.
The thread is at Google Webmaster Help and this is how Google's Matt Cutts responded:
Nope, it's not the title and meta descriptions. I'd recommend reading up about Penguin and looking into how to clean things up for Penguin.
Which is why I'd love to see an automated actions viewer in Google Webmaster Tools. I know it is a lot to ask but hey, I am asking.
Forum discussion at Google Webmaster Help.
Image credit to BigStockPhoto for christmas penguin