I understand your point. What I want to stress here, is that the links provided all ask the end-user to install a huge amount of modules (dependencies) and (mostly) also want to run a local http service to provide the answer to the original quest: reverse dependency tracking. What module uses/depends-on this one.

Currently, the only publicly available service that doesn't need to install and run an awful lot of local things that provides this information is CPANTS, which is down most of the time, so probably useless for day-to-day inquiries.

I however find the original question a very important one if one cares about their own module. If I write Module::Foo, I'd like to know which other distribution uses that module, so I can see if they are following the API the module was designed for or if they are trying to do dirty trichs. When the latter is true, the module probably needs some extra functionality.

I've quite often extended my own modules based on reviewing how others actually use it. This action doesn't require any communication with the end-user. I can do that analisys purely on my own.

The basic feature to reverse lookup what other modules use Module::Foo is not (yet) available on CPAN, which makes the quest of the OP a very valid one.