Hi Stepanie and Michelle,
I actually removed this tag, but we do use some other tags.
We mostly do this to segment our program results.
Audience: Press, Prospects, Customers, Employees, Partners
Business Unit: To compare our different units
Owner: To compare our marketers
Content Type (only for the content channel): Whitepaper, Video, Testimonial, Case Study, ...
Engagement: Targetted on Early, Middle, Late stage in the buying Journey
Solution: To tag our different solutions
You could of course also add tags for the event channel, like: Location, Size, Theme