YouTube is making it easier for users to add annotations to their videos. Now, you can simply log in and annotate away. Still, they are keeping the separate annotations editor intact in case you want more control.
In addition, it's also now easier to add links to other YouTube pages in your annotations. You can link to other videos, search results, video response pages, etc.
Annotations, if you're not aware, are basically little notes you can add to your videos. You can explain a video, let a user know of an updated video, or express pretty much anything within YouTube's content guidelines.
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