First, my site has basically disappeared from Google. It doesn't show on any of the searches that I usually check, nor does it show for a search on my company name.
My 3 1/2 year old site also has disappeared from Google. Large hobby/non-profit site with some separate affiliate pages. Traffic went way down after the mid-December update. Now, with this update, it's non-existent. I think I had 4 unique vistors from google yesterday (aside from google images).
Glad I'm still getting traffic from Yahoo and MSN. :)