spica42 - 5:47 pm on Nov 1, 2012 (gmt 0)
From first hand experience, It's a symptom of sites affected by either Panda or Penguin (or both).
Yup. I'm trying to find out which and trying to solve it as well. Heck, we may have been hit by the EMD as well. I'm starting by:
1) removing all the duplicates on my test site and other sites that I control.
2) If the content appears on sites i do not control, then I'll rewrite them. (That's more than 1000 pages)
3) For the EMD, I'll reduce the usage of some keywords.
What else should I do?