Yes. I was one of the first Justin.tv investors. I think my final return was about 97x, so that's pretty good.
From my perspective at least, Twitch was essentially a re-branding. Basically, they saw that gaming content was popular on Justin.tv, so Emmett decided to move that on to a dedicated site. Ultimately Twitch far eclipsed the justin.tv site, so they shut that down to focus entirely on the Twitch side.
Based on the Startup School podcast episode I heard with Emmett, it sounded like it was less that gaming was popular (I think he said it was 2% of traffic) and more that it was the only content that Emmett actually liked watching. (Not trying to disagree with you, given that you were there, more trying to give another perspective.)
From my perspective at least, Twitch was essentially a re-branding. Basically, they saw that gaming content was popular on Justin.tv, so Emmett decided to move that on to a dedicated site. Ultimately Twitch far eclipsed the justin.tv site, so they shut that down to focus entirely on the Twitch side.