I have downloaded some lectures about computer science to watch. Some are from University, and some aren't.
I noticed the following:
I pause fairly often, and sometimes watch other videos instead then go back, or if I want to have some other sound (music, person talking).
I also pause sometimes to read the blackboard or slide, or consider something the lecturer said. Also if I don't understand part, or have a question, I might go find out the answer before continuing. Also I might try doing one of his examples.
I also need to have the option to pause if I think of something cool or important that I want to write about before I forget.
I skip forward or back in the lectures sometimes.
So so far: parts of the lecture are too fast, parts are too slow, parts are boring, and I rarely want to hear it all in one sitting.
I multi-task a lot. I am writing this with a lecture on. I also burned DVDs, chatted with people on AIM, organised files better, and read news articles.
For especially interesting parts, I watch with my full attention, but for most parts I only pay half attention. Sometimes I stop listening and miss parts. Later, I might or might not go back to hear it.
Missing stuff is OK. It's not important to understand everything the lecturer says. Not all parts of a subject are best learned through a lecture. Some gaps in my knowledge will be much easier to fill in when writing code, or watching a different lecture, or reading a book, or talking to someone.
Missing stuff does not make it impossible to learn about the later things. There are a lot of ways to understand later concepts without the previous concepts. Often I can just assume some feature works the way he says it does, and then the later features make perfect sense. Often later concepts are separate from earlier ones (perhaps they are both building blocks relevant to the conclusion).
So overall: I like to have, and extensively use, control over when I hear what parts of the lecture. Sitting through an entire lecture at once, not doing other things, is never ideal. It's not important whether I get the main point of the lecture or not.
In conclusion: the format of school lectures may be hard to change due to the practical problems presented by having in-person lectures with many students at once. But they are far from ideal for learning.
Lecture Links (Lisp stuff):