You can now reply to topics in the Google Mirror category just as you would any other posting. This means that you will no longer have to send emails to the INA Google Discussion group to participate in topics originating there. Just hit the Reply. (Of course, you can still choose to send email replies to the whole Google group.)
There are a good number of active participants on Discourse, as well as spikes in non-member page views during active discussions here. Removing the “no reply” restriction on Google Mirror postings will allow people to use just Discourse. It might also motivate some non-members to get a Discourse account in order to see and participate in the full topic thread (the one with Google and Discourse postings.)