My answer is, Since people are having smart mobiles and everyone is connected using either whatsapp or facebook, it is better to post your youtube channel in whatsapp group and facebook group and link them into social pages.
It will spread to people who quickly and ask them to share as many as they need.
It will be helpful to you have them as your publisher than your reach to every person.
One approach I use when I want further exposure is to use other social media channels to further broadcast the content out. For example, if you have a video specific to a topic, you can use hashtag names for that topic in your post/tweets along with the link to your video. Those who are following those topics, will see the video post in their their feed.