Do you consider video "serious content"? Your shut-in cousin might send you great cat videos, but are you going to go searching for them? The volume of searches on YouTube seem to me to say that something is happenin' here. Search is an act of volition - you have to be looking, and you have to have at least something in mind to type in the search box.
Is your company represented on YouTube? If 1 out of 2 people on the Internet are on YouTube...maybe you should consider doing something.