Todo Tags

Microsoft To Do adds "steps, importance, notes, tags, and categories" to a task (Managing tasks), and a tag gathers every task carrying it into one view.

Why deferred

A tag earns its place by gathering: "everything tagged #errand, from every list". That is a view across every TodoList — the smart lists' cross-resource read. Inside one list, the importance star, the sort and the search already find what a tag would. The resource itself is already tagged (tags), which is what the explorer gathers by.

Revisit when

The smart lists ship a cross-resource read of todos, so a tag has somewhere to gather into.