There is more to a startup than just code. For example, from the sounds of it the producer currently seems to be the person with the highest workload at justin.tv (except for Justin, who is working 24/7).
Of course, but what do you want to bet most people with a "great idea" have anything more to offer than that?
Before Justin.tv launched, I imagine there was a lot of coding/testing involved. Most start-ups don't need a TV producer even after they have a product.
the one thing worse than secret ideas are the "like X but for Y" startups... eg "It's like Digg, but for Nerf Herders! We've done the market research, honest!"
(sure there are exceptions to the rule; "Google, it's like AltaVista...")
Those crack me up -- what are they even bringing to the table? "You do all the work, and we'll give you a small percentage."