Actually, one of Tom's core arguments was that Google just happens to be policing content better than its competitors. While I can't claim to know for certain

Actually, one of Tom's core arguments was that Google just happens to be policing content better than its competitors. While I can't claim to know for certain exactly what content Facebook moderates, it most certainly does moderate. Is it purely a coincidence that the entire ecosystem on FB is noticeably 'cleaner' than its predecessor MySpace?