Sgt_Kickaxe - 11:03 pm on Nov 17, 2012 (gmt 0)
Great question Diberry but if Penguin is doing anything along the lines you suggest it is probably trying to collate related pages from a site so that it can rank one domain 20 times in the top 25. This reduces the spam people find by pushing spot #2-10 off of page #1 where most clicks happen.
Lately when I have to add a -youtube.com to a search I'm finding a different site has 30 pages indexed, and another, and another. It takes computing power to create all these groups!