Maybe it is not appropriate to post this topic here, even I can't get any of your ideas, that will be Ok. My auntie told me that she has been suspecting that her little kids are looking at some "illegal" sites online. She put a free web blocker on the Mac computer, but they might be finding loopholes. She wanna install some child-control program to see what's going on. There are so many choices since I searched for child-control for Mac, like Mac keylogger, keylogger Mac and remote Mac keylogger, really dazzling. Do you have experience like this?

Those are keyloggers, they log keystrokes, not sure that is what you want.

Mac OS X comes with built-in parental controls.

http://gigaom.com/apple/kid-proofing-a-mac-with-parental-controls/