Blocking advertising is one thing; blocking entire categories of websites from loading at all is a different matter. The desire to do this comes up most often for parents who want to prevent their children from seeing certain kinds of sites, for public institutions such as libraries that want to do the same for all their patrons (but especially children), and for companies that want to restrict what sorts of sites their employees can view at work.
Mac OS X's built-in parental controls offer some filtering of web content, but this capability isn't as thorough, flexible, or bulletproof as some users prefer. Hostal, covered earlier, also lets you block sites with adult or other undesirable content, but it works only with the specific sites on its list (or those you add manually) — it can't dynamically determine which sites may contain offensive material.
For more on using Mac OS X parental controls, see Chapter 3.
If you want to go further in blocking sites with questionable content from appearing in browsers on your Mac, you can try one of the following software packages:
ContentBarrier. This program blocks all Internet software on your Mac from accessing sites or using protocols (such as file-sharing protocols) that you deem unsafe or unfit. You can configure different settings for each user and can even manage your Mac's settings remotely. (www.intego.com/contentbarrier/, $49.95)
KidsGoGoGo X. In addition to blocking adult content ...