To be honest, I don't see how this can strongly imply that Google is doing mass manual reviews of Web sites. But let me show you a thread that randfish pointed me to at SEO Chat. The thread is named SERPs quality team - EU center, and in this thread, a member named damalo said that Google came to his university to discuss jobs available at Google's EU headquarters in Dublin. The main job they were pushing was "SERPs quality team". Here is a snippet of the post:
One of the jobs areas they mentioned was a task group that was being set up to review SERP's quality. They said it was a new team and that they needed alot of people for it. Perhaps these people will be responsible for going through the mail they get from dissatisfied searchers and webmasters alike? I dont know - But thought it was interesting all the same.
I think some are relating this to the sandbox and that Google lines up sites to be reviewed manually before getting into the SERPs. I doubt that and so do many. So let's take it for what it is, a team to do quality reviews of random search results, to answer quality questions and to clean out the spam.