If your daughter is really technology-savvy, then your best methods will be an inconvenience at best.
That said, I use a combination of OpenDNS, Adblock Plus and the Firefox extension Procon Latte.
https://addons.mozilla.or...refox/addon/procon-latte/It can be locked down pretty tightly, supports whitelists, blacklists, objectionable-word replacement, all kinds of stuff.
On Chrome, Foxfilter does alright, but it costs $9.99 a year to get it password-protected.
http://www.inspiredeffect.com/FoxFilter/If you use OpenDNS, make sure you use the dynamic IP update service, and make sure your router doesn't insert a third DNS entry, because if a DNS lookup fails for any reason, the third entry will then allow access.
http://www.opendns.com/support/dynamic_ip_tech/https://forums.opendns.co...nts.php?DiscussionID=1684K9 looks pretty good, but is Windows and Mac only (not hatin', just sayin'...) so my solutions apply to Linux users as well.
If you ever want to lock down a Linux computer beyond browser plugins, it'll get complicated, but routing access through a proxy running DansGuardian is a good choice.
http://dansguardian.org/?page=whatisdg