I need it for school...
I would definitively choose facebook.Its very useful and I can earn alot from it. http://funadvice.com/r/bq5eom5mj7h
None of those, I can't go wrong with FA, that's my fav site. Sorry didn't really answer the question though
Facebook, I guess. I don't use Tumblr or Reddit and rarely use Youtube. Only one I sort of use is Facebook.
I dont have a Tumblr so I dont know what its like. -Youtube. Endless hours of wasting time :3
Of those four - Reddit ... particularly the AskReddit section.
Out of those choices, tumblr. But FA is my favorite.
"FunAdvice. " There is no competition.. .
Facebook, I like the games. >:]
Youtube if not of course FA :)
Youtube is the best
FA and You tube