Reddit for me, by FAR. My channel has just under 1m views on my videos now and about 500k of those are straight from Reddit, no joke. Find the right subreddit, create an attractive title, and most importantly, the content has to be interesting and relevant... In my case, I post glitches about a popular multiplayer game, and when something like that can give you an advantage on other players in the game, of course everyone wants to know, and it will get a ton of views. Luckily, this sort of allows me to bypass the need for a super good quality video because the INFORMATION provided is what people enjoy. But for the most part, if you don't have something super well done or headline worthy... you won't get far on Reddit.