Hot link protection prevents other websites from directly linking to files and pictures on your website. Other sites will only be able to link to file types that you don't specify.
An example of hot linking. Say I like the image on your website, and I want that image on my site. If I use the full URL of your image on my site, then the image is downloading from your site every time someone looks at my site. This means I am using your bandwidth for the image. When you enable Hot Link Protection, then I cannot steal your bandwidth anymore.
To enable / disable hot link protection, please do the following:
1. Login to cPanel and click HotLink Protection.
2. Make sure the domain name you wish to protect is in the box called "URLs to allow access".
3. In the box called "Block direct access for these extensions", provide the extensions for which you would like to block.
4. We suggest you check the box for "Allow direct requests".
5. Skip the "Redirect request to this URL" box and hit Submit.
6. You have now protected your images from being hot-linked. Just be sure that all of your additional domains are in the Hot Link list.