Based on my communications with several folks and our observations on those sites whose rankings we monitor, it would appear that sometime late last week (or over the weekend) Google shifted around some rankings. Our best guess as to what happened:

  1. Global popularity/authority of a domain was slightly devalued when calculating rankings of deep, internal pages (and/or)
  2. Deep links from external sites to deep content pages is now slightly more valuable

I don't like to make guesses like this without significant evidence, but at this point, I feel fairly comfortable making this assertion. We've seen traffic to large "Wikipedia" style content drop off a bit while more targeted, link heavy pages on domains with a less authoritative profile have gained in both rankings and traffic.

For most SEOs, this is a good thing. For those of us who consult with some of the web's content behemoths, the picture is not as overwhelmingly positive.