Tags are a simple, but incredibly powerful tool for identifying different talent pools within a database.
You simply mark all the candidates whose labels you want to edit, select the action "Mass labeling" and in the panel on the right side you plainly add or remove labels from all marked ones. That the tag you want to add doesn't exist yet? No problem, you can start it right as you type!
Bulk tagging can help you significantly, for example in situations where you use a tag to indicate a status - I will call applicants with the tag "Not successfully Called" and remove it from those I successfully called. Or the other way around, I select potential talents for a certain type of position and I want to approach them gradually - I will therefore add the label "Approach with an offer of IT positions" to them.
But of course, I can also mass label different skills (for example, I will select applicants from all junior SQL positions and give them the label "Junior SQL") and I can catch up or correct the fact that I did not label candidates systematically in the past.