I like youtube channels that have active communities in the comments.
What are your favorite youtube channels?
rd95 suggested this post in the comments section of a post about favorite websites.
Jessie Cox -Lore-heavy Let's Player, aligned with my sense of humour.
Objectivity - Various Cool Stuff
Numberphile - Mathematics
Periodic Videos - Chemistry
Computerphile - Computer Science and Hardware
Sixty Symbols - Physics/Astronomy
QI - Official BBC channel dedicated to panel show QI.
NPTELHRD - Indian polytechnic lectures, content in English.
MIT OpenCourseWare - MIT lectures, that's it.
Dr Cris Tisdell - Clear hands-on introductions to various mathematical subjects.
DrPhysicsA - Physics lectures from 'A Levels' up to some of the upper undergraduate courses.