Hi Georg, let me begin by stating I am new to SEOmoz and quite a newbie when it comes to SEO but I too was hit terribly at the end of April. I'm not sure if my situation could also be the reason for your issues. I thought I would throw it in the mix just in case because through my search for answers I found many others were experiencing the same issues and because of the algorithm changes most were faced with the question "Did I get hit by Google?" My site dropped out of search, pages where I once appeared on the first page were either on page 55 or I couldn't find them or I gave up looking after page 60. I would search for exact post title and either I wouldn't appear or my homepage would appear. I reached out to my web developer and he insisted that it was probably a penalization from Google. I didn't believe it could be true because I never participated in any type of link programs, I didn't know what cloaking meant and I couldn't redirect a url even if I wanted to. Then I received a crawl error for this page /wpp-app.php/service. I reached out to the developer again and he stated that Google should not be crawling that page. I remembered the developer had performed quite a few plugin updates and I think there may have also been a WordPress update around the same time. Through my search I ran across the SEOmoz keyword analysis tool, when I tried to enter one of my keywords it wouldn't return a report. After trying several keyword density tools and not being able to run a report I looked into my page code and I found that my All In One SEO plugin was no longer loading properly and apparently it had a conflict with WP Super Cache. It started to make sense because at one time Google would return my generated meta description whenever I entered a keyword into search now they were generating a snippet. Also none of my SEO titles were displaying. I also found that my sitemap was not updating properly. That's when I ran across this thread - http://productforums.google.com/forum/#!topic/webmasters/o9VYAneofdM As it turns out there was a problem with the plugin (Google XML Sitemaps) already generating a virtual robots.txt. Also I found with the updates changes had been made to my .htaccess code. In fact, Antonio, the WP htaccess Control plugin developer jumped in to help me (thank God). He changed my robots.txt to add blocking for the /wpp-app.php/service. Within two weeks my pages started to return in search, in fact the other day I started searching for each of my posts and they all seem to have returned to where they once were. I was very concerned because none of my posts published from May 12 on had page rank but Stuart Kerr (a member here) told me that the page rank toolbar tool doesn't update daily but a new update should be coming through soon. I am hoping that each of the new pages will rank once the update is in place. Through all of the researching I decided to reach out to Google to inquire about a manual penalization and thankfully they returned with "no manual site penalization". It's taken from the beginning of May up until just a couple of days ago to get this issue cleared up. I may be totally off base and I apologize if I am but is it possible that you could be experiencing the same? I've read through all the comments above but unfortunately I don't understand most of the discussion but I would feel terrible if I didn't mention my experience just in case it could be the answer to your problem.