A study we did for a client a while back involved a system that made extensive use of video to introduce people to the service. The reaction from participants was completely polarized - they either loved and were enraptured by the videos or quickly lost patience and stopped watching (the videos, by the way, were professionally-produced and extremely well-done.) The participants who stopped watching wanted to dive in and figure things out on their own (see paradox of the active user).
Huddle doesn't build the initial page views around introductory video - instead it shows a closed video area, which the user may open (click to see full-sized version).
This approach seems to have a good balance between discoverability and not getting in the way of those folks ready to dive in.












