Should Google take a more active approach in censoring its content providers? If it does, is it possible that Google could run a foul of Title II of the Digital Millennium Copyright Act and lose its legal immunity for the actions of its user?

Question

How might Google deploy advanced technologies to identify content that is objectionable?

Can/should Google provide advertisers with guarantees about what type of content their ads will appear next to? How could such guarantees be written so that they are enforceable?