tedster - 4:55 am on Feb 27, 2006 (gmt 0)

I'm hearing a lot of reports like this right now, as Google's Big Daddy infrastructure is in the middle of rolling out -- but not yet stable. Here's the important question -- is your traffic affected? If it isn't, I'd just wait it out.

But if your traffic is affected, and pages that used to get search traffic now are not, or are severely depressed, then it's time for a through check-up of your site. These threads have lots of detail about areas to inspect for problems:

Checklist for Sudden Drops in Rank [webmasterworld.com]
Dropped from Google - a checklist to find out why [webmasterworld.com]
Dropped Site Checklist [webmasterworld.com]