greenham13 - 8:38 pm on Feb 25, 2011 (gmt 0)
Another long-time lurker here.
We operate a network of sites. These are all relatively old, original content white-hat sites with really very little professional SEO work done. In aggregate, they reach many millions of US uniques per month.
Anyways, with the recent changes, we have seen that a site is either deemed "good", "bad" or "neutral" in it's entirety and have had all their pages scores adjusted accordingly. Of course, this has different results on rank and traffic based upon strength, competition, etc.
The high-level of what we have seen so far is:
1. 13% of our sites decreased dramatically.
2. 20% of our sites increased marginally.
3. The remainder had no noticeable changes.
The only thing that seems to have a correlation to being an "up" site instead of a down is that nearly all of our up sites have keywords in their domain name. 1 down site has a good keyword in it's domain name, and dropped on all terms except for the name keyword.