Tag Overflow is a great tool for visually comparing:
- How many questions have each tag.
- The overlap between tags.
- Which tags have lots of unanswered questions.
You can even filter it by a tag.
Piotr Migdal and Marta Czarnocka-Cieciura built it for the Physics Stack Exchange, but it works on other Stack Exchanges, including English Language Learners.
