tedster - 5:47 pm on Mar 16, 2011 (gmt 0)
I was just checking analytics for one of the sites I work with and there was definitely a sharp drop in Google traffic on March 12 - to the lowest level in more than a year.
Traffic began rebounding the very next day and now the levels are in line with past weeks. So I'd agree that something happened on March 12 at Google. But since it stopped happening almost immediately, I don't think I'll be analyzing it in any depth.