The docs (Exporter and perlmodlib) say:
As a general rule, if the module is trying to be object oriented then export nothing.
But then perlmodlib also says:
Standard, bundled modules are all expected to behave in a well-defined manner with respect to namespace pollution because they use the Exporter module.
So I wonder, if you go OO and export nothing, do you really need Exporter? If you don't, does that mean that none of the standard modules are strictly OO in this sense, or does it mean they
EXPORT_OK some things because you need to do that if someone wants to inherit from your module? (Is that true?) Or do you need Exporter just to be able to
use MyModule; ... = new MyModule?