YouTube is a cable network with nothing but public access on. There are literally billions of videos and with over two billion video views per day, there are a lot of people tuned in.
Most recently YouTube has become a place for companies to post interesting content for consumption by general users. We just launched one of these channels for Cisco
The reason they are posting it on YouTube rather than on their own websites is obviously the audience, but it also indicates on a broader sense the acceptance by corporations as a place to invest. What this means to YouTube (and Google) is a change in the opportunity to convert YouTube as a place for premium paid content.
Imagine this: what if instead of pulling down videos that are posted by people who don't own the copyright, YouTube instead relegated them to a premium area of the site? Revenue generated by this premium channel would be distributed to copyright owners relative to the percentage of premium viewing time. This would provide copyright owners with additional revenue generating distribution powered by army of volunteers. This model could be applied not only to top tier content TV and movies, but also to home grown content via a premium toggle managed by the contributor for each video. The model for payment from the viewers would be a monthly subscription model - something that's already been proven viable by Netflix.
Even a year ago, this scenario may have seemed far fetched, but as big companies continue to buy-in on YouTube it's a revenue stream waiting to happen. One that could potentially turn YouTube into the biggest source for commercial video content in a very, very short time.