I have wanted some kind of filter on my network for a long time.  I wanted one because my children are eventually going to grow up and to protect myself.  I looked at commercial products, but I'm cheap and none of them seemed to work that well.  They all had to be installed on a per computer basis and could easily be worked around.  What I really wanted was something that would sit at the gateway of my network and act as a proxy/cache/filter.  I looked at open source options such as dansgardian and