In over 10 years of traffic and sales records, I have NEVER seen a year where traffic drops off in volume or most importantly "quality" as it has this year. I say it's still part of the March 10th update.
Now, on Monday the 9th or April, a month later I see Google is still unable to detect black hatters.
I just saw one site that is using a new tactic of keyword loading his meta title tag, separating each of five phrases with pipes. Guess what...he's on TOP! Amazing!