When you upload a video to YouTube the default setting is "Standard YouTube License" but you actually can choose "Creative Commons"
Why Creative Commons? Unless you are trying to make money off of your content, I would argue why not. It is nice to share.
You can tell if your video is set to creative commons by going to the video manager. Next to your title you will notice a little icon of a person letting you know that it is creative commons. If your videos are not set to creative commons, click on edit and chance the license.
YouTube has this amazing feature for editing videos. When you are in the Video Manager at the top there is a black bar, you will find the option for Video EDITOR.
Video Editor allows you to edit not only your YouTube video but to insert clips from other people's videos. I have found on several occasions where I wanted to use a portion of someone's YouTube video but do not need all of it. If the person has set their video to creative commons then I am able to edit down just to the part that I want.
Video Editor also allows me to easily add music to my videos, which helps me to avoid copyright violations.
As teachers we have all had more and more work dumped on our plates and the way to save our sanity is to collaborate and work together. This starts with sharing our work with a Creative Commons licence to allow other educators to use and modify (with credit).
Here is the link to the official YouTube page on Creative Commons