Google is taking the YouTube model into the realm of corporate video. An enterprise version of YouTube is in the works, according to several reports. It would seem to be considered a more interesting way to distribute training videos, corporate communiques and public relations messages.
Corporations currently distribute video by any number of means--closed TV networks, DVDs, intranets. A CorpTube would simply make that type of distribution available to companies without the resources to develop more complicated networks.
Google's ongoing efforts to dominate the Web already include Maps, Gmail, AdWords, AdSense, Calendar, Books, Blog Search, Labs, Orkut, Photos, Hairdo and Carwash (prove the last two aren't in development), and now, corporate YouTube.