writes "A newly-issued Google patent for Rendering Advertisements With Documents Having One or More Topics Using User Topic Interest describes how to detect the presence of children by 'using evidence of sophistication determined using user actions' and tracking their behavior using the Google Toolbar and other methods to deliver targeted ads. Which is interesting, since the Google Terms of Service supposedly prohibit the use of Services by anyone 'not of legal age.' The inventor is Google Principal Scientist Krishna Bharat, who is a co-inventor of another pending Google patent for inferring searchers' ethnicity, reading level, age, sex and income (and storing it all)."
Ok I'll be the first to admit that this is greek to me. Someone smart figure this out and post a comment translating patentese into english.