I have had a catastrophic decrease in traffic since the 6th. I manage a site that sell sports apparel. It's only a couple of month's old. Traffic was increasing well for only being live since the end of January/early February.
On April 6th, traffic decreased by almost 50%, on April 7th, it decreased another 67%, and today were off to a worse start. Organic traffic from Google has dropped off by almost 80% since the 6th.
There's no apparent reason to this. All of our content is 100% unique. So I don't think we've been caught in the Panda update, although there's no way of knowing for sure. Our content hasn't been scraped either.
I'm leaning towards Google testing, but again I don't know for sure.
Do you think it's possible the the site was reported as spam and Google took that "suggestion" and penalized it? I know wit the Chrome extension you can block domains from your search results, and Google "looks" at the request.