I seriously think google is fucking with us or in such a mess that they don't know what they're doing.
My keyword gets over 300K searches monthly. Medium competition. I was always page one, position 10 ... till penguin hit.
I did nothing at all to the site, nada, zip, ziltch ... (oh sorry I upgraded my theme, but that was about a week after penguin hit).
About 10 days ago it started to pick up again, and now its in position 5 !!! Funny thing is all my old competition (with the exception of 2 sites) were wiped out from the 1st page.
So what conclusion can I draw from this? I feel like sticking my head in the microwave.