We've got ongoing discussion threads on a couple of topics:
Many results from one site - Host Crowding vs Brand Authority [webmasterworld.com]
Matt Cutts Explains Change to Unnatural Link Warnings [webmasterworld.com]
I'v removed a few posts on these topics. The above are ongoing issues and not something new - so let's not post about them here. This thread is for tracking new SERP Updates and changes as we notice them. Thanks all.