I've been using this for months, I thought BGOL knew?
It's how I keep my dumbass clients from using Limewire to download songs.
It damn sure help me, bruh!of course we all could have found it by doing a strenuous search but hey, this simple ass post helped alot of people...
I thought everyone knew about this, here is a fire fox plugin that allows downloading FLV, 3GP, MP3, MP4, 720p HD and 1080p Full-HD qualities from youtube
https://addons.mozilla.org/en-US/firefox/addon/10137