[ndvgnkvu] Porn blocker as history and cache blacklist

Repurpose the list of sites in a porn blocker or other parental control software as a blacklist of sites not to cache or store in browser history.  Because the list of sites is public -- included in the publicly available porn blocker -- the user can plausibly deny even knowing about the sites, which could not be done if the user had to hand-create a blacklist.