I had a site tank a while ago though the rankings seemed to slowly decrease, initially thought it was link loss, after that figured it might have been a Penguin or Panda penalty, but nope, just received this message in webmasters:
Some manual actions apply to entire site
Thin content with little or no added value
This site appears to contain a significant percentage of low-quality or shallow pages which do not provide users with much added value (such as thin affiliate pages, cookie-cutter sites, doorway pages, automatically generated content, or copied content). Learn more.
Site still receives traffic though so I was fine with it. The site is a typical Amazon affiliate review site with an Amazon affiliate theme named Amazillionaire. The site has about 20 reviews, and a couple of overview pages for hair dryers, flat irons and hair straighteners and is categorized as such as well. It's all reviews and monetized pages so not much of a surprise it received a manual penalty (nothing about links though which were as artificial as they can be).
Wonder what it takes to get this penalty lifted, I will do some redesigning and add some random articles to see if it makes any difference, will also do some demonetizing work.
No idea if that's enough but hell we can try!
First time I received a thin content manual penalty so pretty excited and food for another case study on my site how to recover from a thin content penalty with the least effort as possible obvious (probably will be declined first time but what we got to lose? A site that didn't rank anyway lol
I received this message on the 5th of October 2014, quite recently against my surprise so I guess there was already some type of Panda/Penguin penalty active.