I thought that Neo had that feature disabled. It may have been an error if were getting emails about subscribed threads earlier. We used to have a problem with the server bogging down from the load of sending out the emails. But Neo will need to clarify the current state of this feature.
Yes, I disabled it. Recently I enabled it, experimenting - but the volume of mail can be heavy on the server and sometimes the addresses bounce. I'll have to check to see if it is enabled or disabled at the moment.