I am affected too by these updates. An old site, with multiple improvements seem to drop in rankings with every new update. In the first stage I was thinking that the website has bad backlinks.
The latest week, another website (totally new) was affected by Panda, in a very unusual way. The article pages are not ranking anymore. Instead of the articles, the website is ranking on the 12-15 page with another pages, just because the title of the article is in the blogroll.
Google is not able to see that the article is fully published and believes that a simple blogroll title is more relevant than the entire article. This is the most unusual comportment I've seen in few years of web-development / SEO.
The new website (penalized by Panda too) has 100% natural links, I've didn't any link-building for it, just to see how Google will look at it. In the first weeks the results was interesting (good) but after this update, all the new posts was unable to rank.
I want to identify the factors of Panda but I need your help for that. From my experience, Panda can be determined by:
- a bad architecture of the site;
- possible disturbing ads (small distance between ads and text);
- possible duplicate content, but another type of duplicate content, generated by the rewritten articles (Google can detect which articles are rewritten);
- excessive internal linking;
- multiple articles with the same subject
The latest three points are just my thoughts, I cannot be sure if is something real in these affirmations without the confirmation of other webmasters affected by Panda.
Can you confirm what I believe ?