I have been working with a class on “podcasting”, which isn’t really true to that term. Students created fairy tales with illustrations on paper, we scanned those using a flat bed scanner, then imported the images into Windows Movie Maker (included in XP) and students recorded the narration. After adjusting the narration to match the illustrations, we exported the movies and put them up on the teacher’s webpage. There is nothing here that is technologically sophisticated: A scanner, microphone, internet connection and a teacher webpage (of which there are several free options out there).
This is where the struggle began. I wanted other students and parents to be able to post comments about the videos in a moderated environment. In other words, I wanted the teacher to be able to ok the comments before they show on the internet.
Ultimately I chose Scoop.it even though it was not perfect. Currently there is no way to make a “topic” private, but there is a way to configure it to send non-scoop.it member’s comments to you via email to ok them. Scoop.it member comments are unmoderated, but I hope this won’t be a problem.
Scoop.it is one of several new websites which “curate” material from the web. In other words, the content needs to be hosted somewhere else, then is fed into scoop.it like a magazine. So we used Vimeo to host the videos and scoop.it to pull them together in one place and allow the commenting.

Scoop.it and vimeo
Some advice:
The original name for your topic must be unique (not used by another scoop.it). I found that I could later change the name, but the URL (address) continued to contain the original topic name. This allows (I hope) you to hide the topic from the world but giving it a more abstract name. I am not including the topic name, because since this is a public post, it would allow people access to what I tried very hard to make private. But let’s say I named the original topic “our perimeter videos” and then later changed the topic name to “878perimeter”, 878 being the address of the school or whatever. Now the scoop.it would be at the url scoop.it/t/ourperimetervideos but you couldn’t search for it in that way. I also put gobbledygook in the “tags”, so it couldn’t be searched by tag. Finally, I configured the topic to not make suggestions for content from anyplace (annoying to me, but visitors don’t actually see this stuff anyways).
Mission accomplished. Hopefully. We shall see how the commenting goes.
Oh, and if you want to see the original videos (no commenting allowed), go here.