There already was a request to Burninate the "custom-module" tag and now I see it's rebirth as custom.
custom-module doesn't have any meaning because:
- A question tagged custom-module would not get a different answer, as the code used for a custom module is not different from the same code used from a module that is hosted on Drupal.org, and which is not a custom module.
- There isn't an expert of custom modules.
The same stands true for custom, and it's even worse, because of it's even wider scope.