Is it a report or anything like that, that could display a list of all tags together with a count of contacts with each tag?
In D7 this can be done use CiviCRM Entity and Views and Views Field Views
CiviCRM Entity can give us a View with the data from civicrm_entity_tag
but, there is no 'Relationship' that I can spot to the civicrm_tag table to get the name of the tag, hence you get a table with the Tag ID and the Count. Not so useful.
With views_field_view you can make another view based civicrm_tag to get the tag name, use the Contextual Filter of the tag id
then pull that View in to the first one and apply the same Contextual Filter and bingo you have your table of Tags with a count of entities using it.
PM me and I will zip you the views if you don't want to start from scratch.