We have finally figured this one out, and it is not pretty.
Somehow or another, @ned has gotten onto the Akismet spam list – probably through the IP address.
This may be because Comcast rotates IPs, and Ned may have gotten a rotten new IP.
We are trying to figure out how to get Ned off Akismet’s list. This post shows now because I can manually un-spam the post, but Ned probably still can’t reply.
I went through the spam posts (which I normally never do, but will try to monitor for false positives in the future), and there have been a couple of other false positives in the past. So if you try to post and it won’t show up, it is possibly an Akismet issue.