tedster - 4:15 pm on Nov 19, 2010 (gmt 0)
This is apparently a big deal for Google - because there have been other significant iterations that did not get any official announcement. So either this is a big deal, or they've decided to make more announcements, keeping webmasters more officially informed. Since we tend to think "the sky is falling" when we're not informed, this might even be a kind of proactive damage control.
The first change beyond two results per domain was last August:
Google Announcment [googlewebmastercentral.blogspot.com]
Our Discussion [webmasterworld.com]
So now I'm wondering what additional criteria have been folded in that can trigger multiple results.
Is it just that some queries have navigational intent that is somewhat ambiguous, so two sites can now get four results?