Web Site Filter od serv-inc

The trigger words are a regular expression that was taken as-is from the (GPL-licensed) DansGuardian.

If you also need to hard-block certain words or URLs -- block every page where they appear --, consider combining this filter with word/url-based blockers such as ProCon Latte. Or also have a look at Fox Web Security which blocks based on hostnames, relying on services like OpenDNS, Comodo, Yandex.DNS and Norton.

This add-on can augment the above by its score-based filter.