Once Google has significant amounts real human ratings on the usefulness of a site in general or the usefulness of the site given a specific search, machine lea

Once Google has significant amounts real human ratings on the usefulness of a site in general or the usefulness of the site given a specific search, machine learning techniques could then be used to predict the usefulness of unrated sites. I just know I see a lot of worthless junky sites on the first page, and I wouldn't think it would be hard to recognize them using ML techniques, which requires training data.