Revision3, the San Francisco startup behind the Internet TV shows Diggnation and XLR8RTV, has raised $8 million more from investors.

Revision3 is one of several companies pioneering commercial video podcast networks. Their shows can be viewed online or downloaded for viewing on portable media players such as iPods or devices like the Apple TV.

The company calls itself Revision3 because they think that television is moving into its third stage:

• Revision 1: Cable, adding general interest channels, catering to ‚Äúmost common denominator.‚Äù
• Revision 2: PC-based Internet video, indy films, no business model, no loyalty, no audience
• Revision 3: TV and Internet converge. iPods, Tivo, mobile, broadband enable mass, loyal audience to shift to ondemand, niche content. Advertising follows them.

The company, started by the co-founders of news ranking site Digg, raised $1 million last year.