Most of us have work, rest & play on our computers. It would be useful for users to be given the option to define "tag profiles", allowing groups of tags to be assigned to profiles that users can define, such as "Work" or "Study".
Once a user has defined a few tags & groups to profiles, when users need to focus on their studies, they can deselect "Work" & "Play" whilst keeping "Study" selected, allowing them to focus on the immediate task before them. Then, once study is done, they can re-enable their other tag profiles at will. This functionality could possibly come under Tag Groups too, but I believe it would be more accessible being at a more global level.
This idea is useful for if a student is studying multiple yet unrelated subjects, as they could create a Tag Spaces profile per subject. Or someone using Tag Spaces for work could create multiple profiles per customer, and so on.