Is Panda rolling now?
I see huuuge increase for domains having issues which feed Panda algorithm.
They loosed visibility exactly month ago and now they are back (we were cleaning index because of duplicate content issues - about 16 thousands subpages removed due to cleaning.

Fun fact - Google totally gives a sh*t about redirecting old URL structure to another so I had to make 404 on every single duplicated/wrong/broken URL and remove 16k URLs manually.

You can laugh loud at me on Dumb SEO Questions hangout. :D