|We used a product called SafeEyes for 5-7 years.
Safe Eyes - Parental Control Software for Mac and PC[^]
At times the interface was terrible, but it always allowed them to:
1. see valid safe sites
2. kept them from seeing bad content
*It provides a way to set up filters based upon each of their profiles.
*Filters are mostly good as you just pick types of stuff you don't want them to see from categories.
*You can unblock sites so that even if they're marked bad for some reason.
*It even successfully blocks advertisements (adblock) for things you choose like weapons or lingerie.
*You can see all of their searches -- to see if they are interested in something they shouldn't be
*Searches can be filtered too.
*Once you install it on their PC / laptop they cannot take the laptop to another network and get through to bad stuff. Even if they take a laptop to a friend's network (overnight stay or something)
* You can remotely admin the software. -- very cool when they want to see a site and you're at work and it's obviously a safe site. Log in unblock the site and it will be available then.
The software set up can be annoying.
Sometimes in the past the Safe Eyes site would foul up.
Setting up filters and getting it right takes time (but it's worth it)
Sometimes the software (on kid's laptop) just went crazy and had to be rebooted.
Check it out. It might be a lot better than what we had. Haven't used it for 3 years or so since kids are over 18 now.