I've been battling Panda since June. Revamped the site, the layout - even created a tool to find duplicate phrases and sentences across the whole site.
What I found was that any page that had more than 80% similar content and over 150 words received no traffic.
Strangely, groups of pages with very thin content (too thin for sure!) just 50 words or less and 80%+ duplicated across the site ranked really highly in the serps. Which makes no sense to me at all, since it should have been spotted easily by the white stinky bear. The serps in my industry are dominated by spammers and every panda update seems to push these long term spammers higher! Including the 18th Sept update. I saw only one other site getting whacked out.
Seems I just can't get my site to rank again even with fresh articles and well written content. Talk about mind F***.
You know for once, I really wish Pandas were extinct. I've been to China, they're not cute and they smell. A lot like this algorithm.