Smart Firewall doesnt block Custom-made URL address

Hello,

I want to block access a stupid youtube video on my computer, because its annoys me so much- so I put a "outbound-inbound block" rule into Firefox program rule. I Applied the rule but Firefox still can access the video without problems. I want to see a warning page when I enter that video page like "Norton blocked this page" etc, just like Malwarebytes doing for phishing web sites, since I'm playing huge games and I have 4 gig physical memory its not enough for all apps(MBAM have 3 different background process and its eating my memory all day) so I cant run Malwarebytes real time protection. Thats why I wanna use Norton instead

Any ideas?