maximillianos - 2:00 pm on May 2, 2010 (gmt 0)
Google made a blog post about the Webmaster Tools reporting inaccurate indexed pages. We saw ours drop to nearly nothing and then back up to normal again. So hopefully everyone is back to okay in that category.
From the traffic loss topic, we are also what you would consider a large general topic mega-site. We don't have millions of pages, but we hit the six figure range.
As I stated earlier, we are seeing a 10-15% drop in traffic starting this past week sometime. But in the big picture it is all relative. Over the past 10 years we've seen it go up and down, up and down, over and over.
I would recommend letting the dust settle for a few months before making any big changes. Just my opinion.