RedCardinal - 2:57 pm on May 24, 2012 (gmt 0)
@Gmorgan I've also seen the direct opposite where homepages are not affected but deep pages are.
My suspicion is that Penguin is offset largely when pages have high quality links. I've seen cases where a site is badly hit, but one section is completely untouched (in this case /blog/ was unaffected, but the rest of the site tanked).
I've seen nothing as yet to convince me that there was any over-optimisation targeted in this. From what I've seen this is down to out-and-out webspam where links were overtly manipulated and/or pages contained utter gibberish.