"Many"? Article only mentions 2: from life broadcasting to web broadcasting, then to twitchtv (specialized game broadcasting).
The most amazing thing about JTV is that everyone just kept going, even when the circumstances made you want to roll over. Twitch and SocialCam are an object lesson in tenacity.
As Tim noted, props are due to the JTV team, who stuck around and kept building things where reasons to continue were scant, which was often.