Google's patent for Human Editorial Input [webmasterworld.com] was granted in 2006.
The thing that I find important in their system is that no one person on their own has the ability to trash or boost a site. It takes a consensus of independent raters.
Google uses quality raters for a wide variety of projects - including QA on proposed algorithm changes, or the current SERPs for a variety of keywords. Last I heard there were over 10,000 of these folks at work.
Recently I read that behind the scenes Google runs many thousands of proposed algo changes, but only about 500 of them ever go live. That kind of system uses both statistical assessment and human QA.