OT: Do you think medical science is valid, or do you consult YouTube for medical advice?

Yes, there are lots of problems with youtube. One problem is that there are propagandists who create videos in which they claim that what they are saying is what scientists claim. But they are usually twisting the words of scientists to suit their agenda or in many instances straight off lying. Sometimes they will seek opinions of computer scientists on evolution and even then twist their words to make their target audience believe their agenda. Many people knowingly pass on these vids as legit and some are simply stupid to not understand that they are being lied.

But there are some good educational videos. Not just at the highest level but even at basic levels. For example, Khan Academy provides many great vids on intermediate level maths, intermediate statistics, basic calculus, simplified master's level finance, and economics. Or commercial educational prep companies such as Kaplan, Wiley and The Princeton Review etc. can put videos of their instructors. Or some universities put recorded classes of their instructors/professors. While these should not be seen as an equivalent of peer review articles they serve well in educating people who simply need to pass exams or get high-level knowledge of a particular field.