September 2012 will definitely go down as the worst update month in history for my site. Hacking away with all these little quality updates appears to have have finally broke the camel's back and while my traffic remains pretty much the same, since last Friday my conversion rate is in the dumpster. My income this month alone dropped 50%. I know I'm not alone, so retooling my site won't help.
Google is like a brain surgeon operating with a meat clever. They take a swing at the problem, but usually take out more useful grey matter than the tumor they are going after. Some are laughing their way to the bank with useless content, while other useful sites are dying. The crap is being rewarded, while the gold is thrown out. Their slash & burn approach may not have removed our site from the listings, but like the brain, whatever they chopped out appears to have broken all the good connections to our site.
And no, we never bought or developed any back links to our site, whatever was there was 100% natural.