Content filtering is a requirement of the home desktop system configuration build I'm working on. Young children are part of the client base so it's mandatory. DansGuardian is basically the only free option available. It's a server daemon so it has command-line configuration only. Once it's running parents don't need to mess with the basic settings but they need to be able to set filtering controls for children without a lot of hassle. On Ubuntu it doesn't come with any blacklists but third-party lists are available. Shalla Secure Services has one of the most comprehensive list that's free for home use but installing and updating it is also a hassle. I wrote a pair of scripts to solve both of these problems.