I'm looking for a way to filter internet access (homes setting, not business) by means of an 'only allow' access list. In other words, you would have to populate the list with what sites you choose to allow access to. If you wanted a particular PC to only be able to access cnn.com, finance.yahoo.com, and pbs.org - this would be the most sensible approach.
I understand this could become quite tedious, but for some parents, it would be a surefire method for keeping their littles ones from stumbling upon the wrong sites. Of course, the common sense approaches are a must as well, keep the PC in an open, communal room, check on the kids, etc.
But ultimately, for peace of mind, I think that an 'allow only' approach would work best. However, I've yet to find a web filter which allows for this setup. They all seem to have an 'always allow' filter, but never an 'allow only'.