, AndyC wrote

@DeathByVisualStudio: The point is not to have a "standard" way of doing it, the point is to have a mechanism that makes sense for the type of data the application in question is working with. If a hierarchy makes sense, then it can mimic one (or even multiple variations). If it doesn't or if it makes more sense to allow arbitrary pivoting (think Album, Artist, Release Year, etc) then you don't.

But if I decide to switch photo programs, I don't want to have to re-enter all of my tags.