The site that I would probably be most likely to use is Video Note. This site seems like a great idea for online classes. If a teacher would publish their video lecture to youtube, then you can easily take notes on it. A lot of times its hard to listen and write/type and remember where exactly you found that information.

With Video Notes you can tag the exact spot where you are writing about and then as soon as you highlight that place, it goes back to it. This is beneficial because you can listen to that part of the lecture again and make sure you understood what you wrote or change something you might have mistaken.

Video Notes seems like a very user-friendly tool for students. Especially those in online classes where the class is lecture/note taking heavy.