Annotations was a YouTube feature that allowed video creators to add little boxes to their videos. The add-ons could be hyperlinks to other videos, or notes with all kinds of information – jokes, comments, corrections, etc., or even a request to subscribe to the channel.
YouTube announced its decision to discontinue the tool in March 2017. Starting May 2, the same year, users were no longer able to add new annotations to their videos. Existing ones, however, were supported until January 15, 2019, when this too was canceled.
One of the reasons for shutting down the tool was the little interest in it. Initially, Annotations allowed creators to build interactive content. For example, YouTubers used the feature for telling multiple-ending stories or creating online RPGs. They could even provide the content with different points of view for users to switch between. However, these applications of Annotations seemed to have insufficient audience, according to Youtube.
The other reason was Annotations’ incompatibility with mobile devices. When Annotations launched in 2008, people used to access YouTube on computers. However, with the spread of mobile phones, the feature was being used less and less. That is why they build new tools for mobile devices – End Screen and Cards – which still allowed creators to link their videos to other content.