And I wonder how long it will be around…
I was once told that it wasn’t Disney which pulled all the company’s footage which found its way onto YouTube but YouTube itself. Companies like Disney would, apparently, like to have the viral marketing leverage that the site provides but YouTube retains copyright of all work posted to the site.
Some organisations make deals with YouTube under which they consent to allow some of their material to appear. So far Disney has not.
[Update: see Correction in the comments]
frizzyLogic 
As it happens, what you were once told is, well, ridiculous. If YouTube asserted copyright over -any- work posted to its site, it would have been out of business in five minutes.
http://www.google.com/support/youtube/bin/topic.py?topic=10550
Thanks for the correction, Correction 🙂
I suspect that what was being referred to in the conversation was lodged somewhere in the YouTube terms and conditions, possibly more specifically the section on “Intellectual Property”, but it’s more than possible that either I’ve misremembered or the terms and conditions have changed since the google buy-out.