I'm probably not suffering penguin as bad as others. Overall, it's like other slow downs (Springtime Seasonal) but I have noticed that google bot crawling has flat-lined.
This could be due to Penguin's algorithm being written to "Find The Crap". No crap, on to the next site.
Of course when it finds all the crap it could end up in search results as an unforeseen byproduct event. Maybe an, "Oh, we didn't think of that", or maybe "The crappiest of the crap goes to the top so it can be easily seen and removed permanently" and "we did think of it, and we don't care if people suffer in the interim".
I thought that this could be one way to explain Google's recent search, search result, behavior.