aristotle - 1:48 pm on Oct 19, 2012 (gmt 0)
I'm convinced that my two penguinzed sites were hit because of listings in free directories that I submitted to in 2006 and 2007. That's the only kind of link-building I've ever done. Now, in going through the current lists of these directories in Webmaster Tools, I'm finding that nearly all of them have converted to paid directories, some charging submission fees as high as $25. All of them were free when I originally submitted. Most of those that didn't convert to pay directories have apparently disappeared. In any case, these are un-natural backlinks, and I'm going to disavow them and see if it has any effect.