Previously, 'related modules' were generated based on discussions in d.o. forum -- if several modules were mentioned in the same discussion threads, we consider them to be somewhat related.
A second module I wrote this weekend makes it easier to moderate your comments. This was another item high on my wishlist. I didn't found anything that comes close, so please let me know if I missed another module that scratches the same itch.
One of the first things requested from a Drupal developer before contributing a module is to check whether the functionality is already implemented in another module.