aristotle - 3:40 pm on Sep 15, 2012 (gmt 0)
This domain diversity update appears to be algo change that attempts to correct problems created by an earlier algo change.
Google has been working on its algorithm for more than 12 years. By now they should have reached a point where frequent major algo changes shouldn't be necessary. Actually, I think they reached that point about 5 years ago, when for a time the SERPs were much better and much more stable than they are now. But then, starting with "universal search", they began making changes for the worse, and since then one bad change has usually led to another bad change or over-correction later, so that the downward spiral in SERP quality has continually gotten worse and worse.