The big problem I see in the implementation of this idea: How does one forum handle the mass of users? I'm not talking about technical issues, more of the user experience. How can all users engage in the discussion without being overwhelmed?

Each user could pick how many other users they want in the forum. They would get a random sample of all the users. Not happy with the selection? Kick that person out of your forum and get another one from the pool automatically.

Yup. I thought about this about a year back as well. Some networks have experimented with micro-sites and social media plugins with this type of functionality, but I'm not aware of anything that has really caught on yet.

We have alot of this on tinychat.

hehe, funny! I thought of that exact same thing years ago, I even registered 'ontvnow.com' for it...

Though I don't watch TV so this isn't directly applicable to me, after seeing it written out I'm amazed that this isn't already common. It's a really good, sensible idea.

It sorta happens with certain shows already, just on Twitter.

For example, in the UK there's a business show called Dragons' Den where people pitch for money for their crazy business ideas. Quite a large number of people tweet about the show while it's on and almost everything that happens. Not quite "chat" though.