Shatner - 2:21 am on May 16, 2011 (gmt 0)
If I apply the idea that Google looks at your site, determines what it believes it should be, and then re-ranks it or applies a penalty accordingly... that could very easily explain why my site was hit.
My site primarily covers one topic, but it also covers several other different (yet still somewhat related topics).
My site has a much higher reading level than other sites which cover my topic.
So Google looks at my site, says this site is type X and should therefore follow this checklist of things. It sees that it isn't following everything on that checklist, that it's a little different from the others, and automatically penalized it.
That really fits. It's a HORRIBLE idea for an algorithm if that's what Google is actually doing, but it does fit.