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