I have been in the program from almost the very beginning and I am glad they are coming finally frank and open about it.
some more comments and caveats first:
-as anything modern in IT, people sign Non-Disclosure Agreements (NDAs) so not a lot can be said from within the circle without breaking its terms.
Having read the interview, I see the chief has also pretty much kept it this way, let alone only for the terms that are already publicly disclosed
-google operates through 3rd party outsourcers and pretty much all non-essential communication is through them and not google directly, that's why the guy can't tell ya exact number about his posse. the big numbers are probably very correct, but I'm not sure about now.
there seemed to be a very big wave of cut-offs and discontinued access for raters about a year ago, a lot of people got the boot and I'm not sure why - my bet is just a sweep of the axe. some were gone for a good reason, others very randomly.
-the raters have a few spaces and forums to discuss their work, open to public and with minimal chance for an NDA break.
-the raters have mods, too, but I haven't seen activity on that from for a while.
-the specifics of the most cases have drawn me to a conclusion that for each surveyed example, there are at least 6 or 7 people working and giving opinions about, before a final decision is drawn, so there is your internal balance and weeding out bad judgement. lemme say it again you cannot single-handedly change Google's opinion about a particular site and particular search term.
-about natural language processing - this is the scary part. you cannot imagine how good are these guys, especially their algorithms. from time to time they let us sneak peek at it and let me say we had a look at some betas (or alfa-s) of correct grammar processing and translation MONTHS ahead of their official announcement to the world. you could tell it was machine-made translation, but it was good, scary good. And I'm NOT talking English only, no,no.
-the pay -it gets delayed about 6 weeks after month's end but is regular and usually not enough for a living, mainly due to the lack of work. first year it was good, very good, but in 2008 it started getting less and less, which is a shame, since it is a nice way to browse the net and get really paid to do it ! ;-)
in those initial months, we were mainly dealing with spam, but recently even that is not so much present.
-the reason they do not pinpoint sites has to do with the entire structure of the reviewing process - we look at a certain page from the perspective of a concrete search term and it's relevance to it, which is a good compromise. also you can get good content AND spam at the same time.
Altogether for nearly two years in it, the terms we are monitoring haven't changed drastically an it can be boring from time to time, but otherwise, you get to see some really weird things people type into the search field.
-altogether, recently I was both happy and pissed off at what their focus of work changed -dumbing down. more simpler and simpler explanations and help for the raters, so no surprise.
-oh, yeah, one more thing. The leaked Guidelines - way beyond old so of not much use for reverse-engineering and helping the SEO guys. good luck with that :)