There are a lot of features of YouTube that aren’t obvious right from the start and are available to you once you log into your account. One of them is Annotations.
The Annotation feature allows you to add text info and text bubbles with arrows and links to your video after it has been uploaded. Annotations are those little red boxes you see on some peoples videos, or the little transparent boxes with arrows. Annotations isn’t just for text notes but can also be used to make internal links inside of YouTube. This is great if you have several videos on the same subject or maybe Part 1, 2, 3 type videos. Using Annotations you can link videos together. This is also great if you forgot to highlight or mention something important in your video and don’t want to reshoot it. It is an easy way to update.
Most videos don’t use this feature at all but it is very powerful.