After a web page banner managed to defeat my anti-porn filters, I found a way to stop such intrusions. The free program is called 'Naomi' and will close the web page whenever it detects offensive material, be it violence, hate, blasphemy, occultism or porn. I am using it as another tool to defend my grandkids and think others may consider it useful as well. Here are some advantages:

...recognizing new sites automatically;
...semantic analysis of web pages contents, addresses and links;
...recognizes the major languages;
...recognizes ICRA labelling system;
...monitoring is not limited to web sites, but covers the whole local internet traffic;
...works with any software application (browsers, most chat and IRC programs);

Also,

...password-protected, chosen by the user during the installation;
...extremely easy to use;
...does not require configuration;
...can be hidden;
...can be used on slow connections, and with any service provider.

By Radiant Morning Software: http://www.radiance.m6.net/