If this has been discussed I apologize for having missed it. While checking on a few other things I noticed that the total number of pages being considered by Google for any given keyword or key phrase has been dramatically reduced. The initial page in serps still looks the same, ie: 278,000 pages for the keyword "widgets" but if you click through to the second page suddenly it's "192 results, we've omitted the rest etc...".
That's a big drop from 278,000 possible contenders down to 192 in total. I'm also aware that a "good" page will appear in serps for dozens or hundreds of different keywords while a poorer page will only appear for a handful making it more likley to rank better pages for longtail keywords even if they aren't completely related. It would seem that a good many pages will now not appear for anything at all.
This feels like a fundamentally different way of ranking pages than we've seen for years.