fathom - 4:22 pm on May 6, 2013 (gmt 0)
I have had the "thing" (maybe it's Penguin who really knows) for around a year now. I read these posts that say I need to build my site for my customers and not Google, focus on making customers convert etc. I thought I did that. Did I spam - NO. I did have a section of related sites. They were mainly related areas of interest sites etc (but here again how far do you stray before it becomes too off topic in Google's eyes?) The site was pretty clean and this is why this Penguin thing irritates me so much. I would consider me clean and many of my competitors spammy.
You have to work backwards to identify the problem(s).
What specifically created your ranks?
Not everything did so weed out what didn't and what's left (prior to your loss) are the suspects.