tedster - 3:02 am on May 18, 2011 (gmt 0)
Wow - 80% is a huge drop. Please do keep us updated as things go forward.
Do you use WebmasterTools? If so, does it give you anything - a message? or a drop in any reported stats?
And since you are on Wordpress, have you checked for any hacks that ended up with parasite content/links?