I use YouTube for many educational videos, songs for learning, brain breaks, and most recently for uploading videos of my students that I wish to remain private except for our class to view.
Here is an example of my channel that is used to post the weather reports that my students did. Using YouTube Capture app allowed for easy uploading!
I found that this was the easiest way to have access to some videos without sharing them with everyone, yet allowing some to see. It is nice to be able to look back and always have these videos even when the kids move on and so do their iPads.
I can see how in the older grades they might have their own channels to keep specific learning videos, as well as creations they have made. This would be a great portfolio of iMovies and other learning videos to show at Open House.