I have long suspected this but now I have seen this with my own eyes. Recently I made major changes on a site. New site titles new content and the site collapsed in ranking. Maybe its their new patent causing this, needless to say these changes were necessary for the long term and I'm sweating the short term. However here is the point of the post. As the site plumetted I noticed these changes to overall stats.
1. Bounce rate up from 48% to 75% 2. Visitor time on site down from 3.48 to 0.35 3. Spam increase and Zombie Traffic 4. Returning Visitors down by 30%
The point is the lower the serp ranking the worse the stats are regardless of the quality of the site. And this is where Panda fails I believe. Once your down the serps you naturally get abysmal results and algorithmically is impossible to tell the quality of the site.
Agreed, duplicate content is a side effect or a sign of the Panda problem that was going on. The core issue was loss of authority.
Also, when people discuss duplicate content, they are often not clear about duplication within the site and duplication of another domain - especially a site that using extensive and non-discriminative scraping for most of its content, rather than real curation of some kind.
As said before I got a Panda hit site, I have really changed the whole site deleted 80% and no it was not crap pages, but when I then look at the top 10 results for different keywords, then I get confused. Those sites have almost no content, lot of links, link exchange suggestions, lot of banners above fold...... so how can we be sure that google has not just add a "random algo" to loose seos, just for the confusion, a kind of shuffle with no logic to it.
zeus have you ever thought about this being a user intention issue? We've got a new thread that just started looking at this angle. The more I hear about your current challenges, the more I think this may be one of the things affecting you.