Surely each diocesan bishop is a pretty busy man. There must be a lot of material, internet articles, journal articles, books on spirituality, books on apologetics, Bible commentaries, elementary school textbooks, university level textbooks, etc. that come to the bishops to approve with the Imprimatur.
So, first of all, who reads them? Not the bishop himself, surely? Second, who checks that they are consistent with the vast library of Church teaching, which is differently interpreted by different people? And finally, does the Imprimatur need to come from the bishop of the place where the author lives? I’d imagine if you sent a controversial (or even by some people’s standards, heretical) article to a dozen liberal bishops you’d get at least one Imprimatur back.
I’m just interested in what these statements mean in practice.