Justin.Tv(Commonly known as JTV) is the website many broadcasters used to use for their live streams. All Gameon casters used Justin.Tv, or JTV to cast.
When watching other broadcast you can also chat with other users.
JTV spun off its gaming division into a new site called Twitch.tv where the GameOn broadcasters cast now. JTV was shut down in 2014 to focus on this new site.