Google has announced that it will slowly begin replacing annotations in YouTube videos with a new Cards format, which is designed to work on both desktop and mobile platforms.
Google said they heard from YouTube video creators they wanted more flexibility with the information shown during annotations, along with mobile support. The new Cards are the company's solution to those issues. Google says:
You can think of cards like an evolution of annotations. They can inform your viewers about other videos, merch, playlists, websites and more. They look as beautiful as your videos, are available anytime during the video and yes, they finally work on mobile.
Because cards work across mobile and desktop and give you more flexibility to share what you want, our goal is to have these eventually replace annotations. But this will happen only once they can do everything annotations can do today, and more.
You can see an example of Cards in our video above showing off the Samsung Galaxy S6 and the Galaxy S6 edge at the 15 second mark. Currently, there are six Cards categories to choose from: Merchandise, Fundraising, Video, Playlist, Associated Website and Fan Funding.
Source: YouTube Creators blog