considering youtube is starting to add their own download links (http://www.downloadsquad.com/2009/01/19/youtube-begins-addin...) and there are already tons of sites and utilities to download them already that haven't been blocked, i'd say youtube doesn't really care.
Those who want their sites/products to go mainstream without ridicule (ExpertSexChange.com/ExpertsExchange.com is a popular example) or false negative impression/bias. This is why people often spend a lot of time to choose a name carefully, especially when you consider the long-term branding and marketing.
