YouTube plans to throw away its built-in automatic sharing feature. After January 31st, the automatic sharing option for Twitter and Google+ will be removed from YouTube.
The reason given as to why YouTube removed this feature is that they have found social sharing works better when the posts are customized by the sharer and can take advantages of the unique features other social media platforms have to offer.
“Overall, this provides a better experience for both you and your followers vs automatically generated posts.” – Jordan from YouTube
You will still be able to add social media links to your channel banner or manually share videos after they’ve uploaded. Videos already shared through this feature will also remain on the other platforms.