From personal experience on both sides of the lecture, distracted people don't learn well. I'm afraid that recording a lecture is just another distraction. Concerning the audio files, why not save them as MP3s on your hard drive? Posting them on YouTube or any other online site, even privately, would push the bounds of "personal use" in my book.
Even taking notes can be a distraction. I had a student that was so involved in writing down everything that I said that she was constantly asking me to back up and repeat myself. Turned out she was terrified of the final exam for the class and wanted to make sure she had everything. I was overviewing material at the rate of about a 3 credit college class every 3 hours and the exam was open book!
Agree completely. OP, I'm not sure that posting lectures on YouTube or anywhere else online, even privately, would be a good idea; actually, it is a very bad idea, not least for copyright reasons, not to mention privacy issues, and speaking personally, I would not favour it. At all. I've had colleagues who copyrighted their lecture notes - and I used to think them paranoid for doing so. Seriously, OP, have you any idea of the boundary between 'public' and 'private' use?
Even if the lectures are long, not everything in them is of equal importance, and one of your tasks is to ascertain for yourself the important points and study them further so that you understand them.
Given the myriad attractions, distractions and entertainments of what are on offer online and elsewhere, I'm coming to the view that some students have a serious problem with schooling their attention span to something as mundane (and boring) as paying heed in class.
Bottom line, you're there to learn not to be entertained. The best teachers will try to do both, but recording a lecture is no substitute for paying attention and thinking about what is said.
Likewise, and this may surprise you, teachers - especially those in the humanities, - do not want an exact repetition of their own class notes thrown back at them in exams and essays. They want evidence that you have thought about the stuff, questioned it, mulled over it, mastered it and understood it. That is not the same as giving back exactly was given out in class, as it means thinking about - critically analysing - what was said in class. And that, in turn, means developing skills of concentration and listening.