According to the support page, “After January 31st, the ability to automatically post your YouTube Activity on Twitter and Google+ will no longer be available. You can still share videos on social networks directly from YouTube via the Share button. Creators will also see an option to Share on social networks/platforms right after they successfully upload a new video.” YouTube claims that this decision was made in order to make sharing more personalized.
“Many years ago, we introduced the option to automatically post your public YouTube activity with your social media followers on both Twitter and Google+. Since then, we’ve found that social sharing works better when the message is more customized and takes advantage of social media features, such as @mentions. Overall, this provides a better experience for both you and your followers vs automatically generated posts.”
We’re sure that some creators will definitely miss the automatic sharing tools, but at the same time we suppose it’s not that inconvenient to share it manually on Twitter, even if it is an extra couple of steps.