I read this more as a "toy problem" - a demo on how to do caching well, than as "this data needs caching, today". i.e. a tutorial, because sooner or later you w

I read this more as a "toy problem" - a demo on how to do caching well, than as "this data needs caching, today". i.e. a tutorial, because sooner or later you will benefit from caching. As such I think it's a well written clear example. But you always need to bear in mind that a toy problem simple enough to demo a technique clearly, is seldom complex enough to need the technique.