Youtube annotations are those sometimes useful but more likely annoying messages that appear over videos on that site. You’ve probably seen them when a video asks you to “Like and Subscribe!” or “Visit here for my merchandise”. They can be annoying.
The good news is you can disable annotations each time by clicking on the video settings through the cog symbol, but there is an easy way to disable them permanently.
Go to https://www.youtube.com/account_playback where you’ll see this page:
Simply click on Show annotations and in-video notifications to unset it and save your settings. Annotations be gone!