After receiving a message to the moderators that contained a question which was basically "why can't I post?", it didn't take me long to find the answer "because you're not a member". This reminded me that it has been several years since I last purged the list of people who are permanently bouncing all the emails that are sent.
So I've just spent the last couple of hours checking the bounce messages of every single one of the 240+ bouncing members, and if they'd been bouncing for over a year, and we clearly have no way of contacting them (email account not known, or been deleted, or host no longer exists, etc. etc.), then I purged them from the list. In cases where the reason for bouncing wasn't obvious, I sent a reactivation request. One of the more worrying sets of victims were some of those with yahoo email addresses, where the mails were all being bounced for "policy reasons" - i.e. yahoo thinks yahoo is a spammer.
So if you used to receive email from the list, but no longer read that account, and instead just view the group using the web interface - you may see that your membership has been revoked. You'll still be able to read the list as normal, so there's no harm done in practical terms. However, in that case, and if you want to post again, can you sign back up with a valid email address, please, and sorry for the inconvenience.
Back to your regularly scheduled prime-time entertainment ...