tedster - 3:41 am on May 18, 2011 (gmt 0)
A couple of other threads here are reporting an odd grouping of events. The first thing is that Sitelink get added or expanded. At the same time, Google traffic takes a huge nosedive, and at least in some cases, rankings begin a rapid cycling up, down, down, back up, etc. A kind ot rapid wave, as if Google is doing some kind of statistical sampling.
That's some odd (and painful) SERPs behavior.