As the OP said, each home (jewish or not) should have an internet filter.
The conversation of wow its by passable and how easy it is to by pass, is IMHO a stupid one. Its a computer, if you installed software to do one thing you can remove that and do it another way. Or you can easily by pass it by not booting to that OS (Bootable USB anyone?).
Its trivia at most to by pass any software based filter. Publishing how to bypass is extremely important as its the only way people will be aware that its worthless.
In general there are 2 types of filters:
1. Software based (worthless).
2. Network based.
Network based filters can further be divided into 2 categories:
a. Premises based protection (open dns enforced on a router, Sonicwall, websense etc).
b. Provider based protection (jnet, yeshivanet etc).
Each of the above has its uses, (a) above is best for companies that dont want to use just one provider. Easy and quick control and the whos/whats and when.
(b) above is excellent for smaller and home based businesses.
If one wants a filter and they are a small or home based business, then using (a) above they can just bypass the physical box and plug directly into the unfiltered Internet. It is therefore probably worthless in small businesses.
The software based solutions has only one use, and that is for a user working in an environment where they will not spend money for filtering, in which case k9 or the likes should do the job.
If a filter is bypassable but how to by pass it is not published, then it ends up being a compliance paper to get your kids into school and nothing with filtering, more like a bus pass that transportation has been paid.