I'm unsure of this my own self. I'll keep you posted when this site moves back to EarthenRing.net (domain mapping may affect what we have set up for those emails).
So, here's the deal. When the formerly 'new' ERN was built, every qualifying Kickstarter donor got an @earthenring.net email address. We had to move servers within a few months, and that meant recreating all the email addresses. At that point, I remade the ones for people who actually used them, partly because I was swamped with many things, and partly because if anyone who was eligible still wanted the email address, I figured they would let me know. Several did, but only a handful overall.
A few months ago, we moved ERN email accounts from that server to Gmail (Google Apps). That made email way easier for those of us who used the accounts, but it also had one adverse effect - it limits the amount of email accounts that can be made for free (10 or so, I think). Any more requires an update to Google Apps for Business, which means ever email address requires $5/month each (or $50/year) - but that would charged to the Apps account holder (He who is called Mox) as opposed to each email account owner paying their share. This would mean either Mox foots a heavy bill (multitudes of what this site costs us now) or he has to ensure that people who use those accounts are actually paying their share to him. Neither would be realistic or favorable in any way, and overall doesn't seem worth the hassle.
So, we have a handful of accounts still available to those who originally qualified, and who would actually use them.