All posts published by a broadcaster's Facebook page will display at Communication > [Broadcaster name] > Facebook > Page posts.
When people like the post on Facebook, they will be listed in the bottom left corner of the post. A an arrow will appear in the top right corner. Click on the arrow and it gives you the option to tag people who liked the post.
Click on Tag people who liked this post and a pop-up will display:
You can select a tag that already exists or create a new tag in this window. Once you've selected the tag, click the Add tag button and the tag will be added to everyone who has liked the post on Facebook.
The option is only available after someone likes the post on Facebook.
If you tag people today and someone likes the post on Facebook tomorrow, they will not be tagged.
You can use tags to distinguish between topics that interest your Facebook fans.
You can also tag unpublished page posts at Communication > [Broadcaster name] > Facebook > Unpublished posts.