Tags can be used to give a short note to selected unit. They can be applied to Users and Devices now. Tags management panel is located in Setting - Organization Settings - Tags
Here you can create Tags with length up to 16 characters (only letters, digits, and spaces) and pick the colors, edit and remove them.
There's an option to create new tag on-the-go in User or Device view: - click tag icon - start typing it's name - press enter or "Create new tag: %tag_name%" Note: the only downside of this method is no color selection.
To unassign tag from unit just click x near tag's name. If you need to edit or completely remove the tag follow to Tags management panel.