diberry - 3:01 pm on Oct 22, 2012 (gmt 0)

atlrus, leosghost is right. I was hit hard by Penguin, and early on an SEO in here insisted I had spammy backlinks and challenged me to prove it. I let that person look at my domain, and he admitted my problem wasn't backlinks. Others have since looked at it and confirmed the same. Penguin is definitely looking at onpage factors as well as offpage - maybe the vast majority of Penguin sites have backlink issues, but not all.