How does the Webfilter of Windows Vista's “Parental controls” work?

Question

How does the Webfilter of Windows Vista's "Parental controls" work? Is it integrated in IE or a proxy?

Answer 1

The controls on Windows 7 disable all other browsers, so it must be IE only. If Vista is anything like Windows 7 then it is probably the same. I didn't see any details about it, so I tried installing it. Wasted a few hours on the whole process.