hmmm…thats a very interesting question. a filter is never foolproof. trust me. im a geek. there is no filter out there that i know of that you cant get around.
blacklists (essentially how filters work) are by no means foolproof…
your best bet if you want to be safe is a whitelist (which only allows certain sites and blocks EVERYTHING else) on which is a list of the sites you NEED…and nothing else, and to have someone else hold the password. but even those arent absolutely foolproof.
the internet is a necessary tool. as necessary as walking in the street. walking in the street, there are many nisyonos that we all face walking in the streets in terms of pritzus, and we have to deal with it, because we all need to walk in the street. we need to use discretion, and i know that is hard when the nisayon is so hard but all we can do is our best.
also in addition to the whitelists…you can use the add ons mentioned above…ALSO…you can have your network traffic dumped to a specific location for someone else to peruse at his leisure…(providing you are on the same network because oif not you would have to email the list to him and that would defeat the purpose…)