[effective]

ok, let's assume that Tags are Wrong™, what about a basic Contextualization of Contexts™?

something like having 3/4 default Single-Context Families: a Generic Context (for tools and whatever…), a Person Context and a Location Context?
(also a Mood Context, if you feel like seriously going for it)

that may sound crazy to purists, but could be a sort of middle way between the strict single context and the chaos of tags