Here's a list of educational websites

ted.com is certainly not an educational website

Courses
https:// www.coursera.org/
https:// ureddit.com/
https:// www.udacity.com/
https:// www.edx.org/

Videos
https:// www.khanacademy.org/
https:// www.ted.com/
https:// academicearth.org/
https:// unplugthetv.com/
https:// www.thenewboston.org/tutorials.php (down?)
https:// www.youtube.com/user/crashcourse
https:// www.youtube.com/user/minutephysics
https:// www.youtube.com/user/cgpgrey
https:// www.youtube.com/user/vsauce

Music
https:// www.justinguitar.com/
https:// www.musictheory.net/
https:// ultimateguitar.com/ (down?)
https:// playbassnow.com/
https:// www.howtoplaypiano.ca
https:// www.teoria.com

Random knowledge
https:// www.mentalfloss.com
https:// www.frickinghomepage.com
https:// www.snopes.com
https:// www.nowiknow.com
https:// www.badassoftheweek.com
https:// www.sporcle.com
https:// www.ifeveryoneknew.com/
https:// www.wikipedia.org

Cooking
https:// www.cookingforengineers.com (down?)
https:// www.cooklet.com (down)
https:// www.reluctantgourmet.com/technic.htm
https:// www.how2heroes.com

Language learning
https:// www.duolingo.com
https:// www.memrise.com
https:// www.bbc.co.uk/languages
https:// www.livemocha.com (redirects to Rosetta Stone)
https:// www.busuu.com
https:// www.verbling.com

Books
https:// www.gutenberg.org
https:// www.librivox.org
https:// www.bartleby.com
https:// www.poemhunter.com

Programming
https:// www.codecademy.com/
https:// www.learncodethehardway.com
https:// www.htmldog.com
https:// www.trypython.org
https:// www.rubymonk.com (down)
https:// www.codingbat.com

DIY's/How to's
https:// www.instructables.com
https:// www.thedailymiscellany.com (parked domain)
https:// www.wikihow.com
https:// www.wonderhowto.com
https:// www.howstuffworks.com
https:// www.howcast.com

Documentaries
https:// www.topdocumentaryfilms.com
https:// www.documentaryheaven.com

Other
https:// www.etymonline.com
https:// www.erowid.org
https:// www.lesswrong.com
https:// www.lizardpoint.com
https:// www.photo.net/learn
https:// www.freerice.com
https:// www.thinktutorial.com
https:// www.thechesswebsite.com
https:// www.investopedia.com/university

Math
https:// www.wolframapha.com
https:// www.projecteuler.net
https:// www.mathrun.net

What's a good one for studying female genitalia? Asking for a friend.

Should be added imo