Here’s a nice chart depicting the top money makers from ad placement inside video clips on the youtube.com. The business potential from content sharing seems strong enough to drive Sony and Universal into building VEVO later this year.
I am a firm believer that there are more ways (other than advertising) to leverage on content at a mass scale. Of course this may require further developments in network access; we should forget that only a tiny fraction of internet access is effectively high-speed. However, this is good example of business transformation in the current economy and social setting (including unauthorized reproduction of copyrighted material – piracy in short).